]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/kern/zalloc.c
xnu-6153.81.5.tar.gz
[apple/xnu.git] / osfmk / kern / zalloc.c
index 0a21dda6a1e6b7fc06ea8e420b9e4a9e3cdc5721..f25e4040768d77eda5cf7fb7878e7148ba494457 100644 (file)
@@ -1,8 +1,8 @@
 /*
- * Copyright (c) 2000-2016 Apple Inc. All rights reserved.
+ * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /*
  * @OSF_COPYRIGHT@
  */
-/* 
+/*
  * Mach Operating System
  * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
  * All Rights Reserved.
- * 
+ *
  * Permission to use, copy, modify and distribute this software and its
  * documentation is hereby granted, provided that both the copyright
  * notice and this permission notice appear in all copies of the
  * software, derivative works or modified versions, and any portions
  * thereof, and that both notices appear in supporting documentation.
- * 
+ *
  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
- * 
+ *
  * Carnegie Mellon requests users of this software to return to
- * 
+ *
  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  *  School of Computer Science
  *  Carnegie Mellon University
  *  Pittsburgh PA 15213-3890
- * 
+ *
  * any improvements or extensions that they make and grant Carnegie Mellon
  * the rights to redistribute these changes.
  */
@@ -70,8 +70,8 @@
 #include <mach/mach_host_server.h>
 #include <mach/task_server.h>
 #include <mach/machine/vm_types.h>
-#include <mach_debug/zone_info.h>
 #include <mach/vm_map.h>
+#include <mach/sdt.h>
 
 #include <kern/bits.h>
 #include <kern/kern_types.h>
 
 #include <libkern/OSDebug.h>
 #include <libkern/OSAtomic.h>
+#include <libkern/section_keywords.h>
 #include <sys/kdebug.h>
 
 #include <san/kasan.h>
 
+/*
+ *     The zone_locks_grp allows for collecting lock statistics.
+ *     All locks are associated to this group in zinit.
+ *     Look at tools/lockstat for debugging lock contention.
+ */
+
+lck_grp_t       zone_locks_grp;
+lck_grp_attr_t  zone_locks_grp_attr;
+
 /*
  *  ZONE_ALIAS_ADDR (deprecated)
  */
 
 #define from_zone_map(addr, size) \
-        ((vm_offset_t)(addr)             >= zone_map_min_address && \
-        ((vm_offset_t)(addr) + size - 1) <  zone_map_max_address )
+       ((vm_offset_t)(addr)             >= zone_map_min_address && \
+       ((vm_offset_t)(addr) + size - 1) <  zone_map_max_address )
 
 /*
  * Zone Corruption Debugging
@@ -178,7 +188,6 @@ sample_counter(volatile uint32_t * count_p, uint32_t factor)
                } else {
                        rolled_over = FALSE;
                }
-
        } while (!OSCompareAndSwap(old_count, new_count, count_p));
 
        return rolled_over;
@@ -190,6 +199,9 @@ sample_counter(volatile uint32_t * count_p, uint32_t factor)
 #define ZP_POISON       0xdeadbeef
 #endif
 
+boolean_t zfree_poison_element(zone_t zone, vm_offset_t elem);
+void zalloc_poison_element(boolean_t check_poison, zone_t zone, vm_offset_t addr);
+
 #define ZP_DEFAULT_SAMPLING_FACTOR 16
 #define ZP_DEFAULT_SCALE_FACTOR 4
 
@@ -201,7 +213,12 @@ sample_counter(volatile uint32_t * count_p, uint32_t factor)
  */
 
 /* set by zp-factor=N boot arg, zero indicates non-tiny poisoning disabled */
-uint32_t        zp_factor               = 0;
+#if DEBUG
+#define DEFAULT_ZP_FACTOR (1)
+#else
+#define DEFAULT_ZP_FACTOR (0)
+#endif
+uint32_t        zp_factor               = DEFAULT_ZP_FACTOR;
 
 /* set by zp-scale=N boot arg, scales zp_factor by zone size */
 uint32_t        zp_scale                = 0;
@@ -217,6 +234,7 @@ uintptr_t       zp_nopoison_cookie      = 0;
 boolean_t       zone_tagging_on;
 #endif /* VM_MAX_TAG_ZONES */
 
+SECURITY_READ_ONLY_LATE(boolean_t) copyio_zalloc_check = TRUE;
 static struct bool_gen zone_bool_gen;
 
 /*
@@ -256,10 +274,11 @@ zp_init(void)
        if (zp_factor != 0) {
                uint32_t rand_bits = early_random() & 0x3;
 
-               if (rand_bits == 0x1)
+               if (rand_bits == 0x1) {
                        zp_factor += 1;
-               else if (rand_bits == 0x2)
+               } else if (rand_bits == 0x2) {
                        zp_factor -= 1;
+               }
                /* if 0x0 or 0x3, leave it alone */
        }
 
@@ -289,9 +308,10 @@ zp_init(void)
        zp_nopoison_cookie = (uintptr_t) early_random();
 
 #if MACH_ASSERT
-       if (zp_poisoned_cookie == zp_nopoison_cookie)
+       if (zp_poisoned_cookie == zp_nopoison_cookie) {
                panic("early_random() is broken: %p and %p are not random\n",
-                     (void *) zp_poisoned_cookie, (void *) zp_nopoison_cookie);
+                   (void *) zp_poisoned_cookie, (void *) zp_nopoison_cookie);
+       }
 #endif
 
        /*
@@ -327,14 +347,14 @@ zp_init(void)
  * of pages being used by the zone currently. The
  * z->page_count is not protected by the zone lock.
  */
-#define ZONE_PAGE_COUNT_INCR(z, count)         \
-{                                              \
-       OSAddAtomic64(count, &(z->page_count)); \
+#define ZONE_PAGE_COUNT_INCR(z, count)          \
+{                                               \
+       OSAddAtomic64(count, &(z->page_count)); \
 }
 
-#define ZONE_PAGE_COUNT_DECR(z, count)                 \
-{                                                      \
-       OSAddAtomic64(-count, &(z->page_count));        \
+#define ZONE_PAGE_COUNT_DECR(z, count)                  \
+{                                                       \
+       OSAddAtomic64(-count, &(z->page_count));        \
 }
 
 vm_map_t        zone_map = VM_MAP_NULL;
@@ -345,14 +365,14 @@ vm_offset_t     zone_map_min_address = 0;  /* initialized in zone_init */
 vm_offset_t     zone_map_max_address = 0;
 
 /* Globals for random boolean generator for elements in free list */
-#define MAX_ENTROPY_PER_ZCRAM          4
+#define MAX_ENTROPY_PER_ZCRAM           4
 
 /* VM region for all metadata structures */
-vm_offset_t    zone_metadata_region_min = 0;
-vm_offset_t    zone_metadata_region_max = 0;
-decl_lck_mtx_data(static ,zone_metadata_region_lck)
+vm_offset_t     zone_metadata_region_min = 0;
+vm_offset_t     zone_metadata_region_max = 0;
+decl_lck_mtx_data(static, zone_metadata_region_lck);
 lck_attr_t      zone_metadata_lock_attr;
-lck_mtx_ext_t   zone_metadata_region_lck_ext; 
+lck_mtx_ext_t   zone_metadata_region_lck_ext;
 
 /* Helpful for walking through a zone's free element list. */
 struct zone_free_element {
@@ -361,14 +381,40 @@ struct zone_free_element {
        /* void *backup_ptr; */
 };
 
+#if CONFIG_ZCACHE
+
+/*
+ * Decides whether per-cpu zone caching is to be enabled for all zones.
+ * Can be set to TRUE via the boot-arg '-zcache_all'.
+ */
+bool cache_all_zones = FALSE;
+
+/*
+ * Specifies a single zone to enable CPU caching for.
+ * Can be set using boot-args: zcc_enable_for_zone_name=<zone>
+ */
+static char cache_zone_name[MAX_ZONE_NAME];
+
+static inline bool
+zone_caching_enabled(zone_t z)
+{
+       return z->cpu_cache_enabled && !z->tags && !z->zleak_on;
+}
+
+#endif /* CONFIG_ZCACHE */
+
 /*
  *      Protects zone_array, num_zones, num_zones_in_use, and zone_empty_bitmap
  */
-decl_simple_lock_data(, all_zones_lock)
+decl_simple_lock_data(, all_zones_lock);
 unsigned int            num_zones_in_use;
 unsigned int            num_zones;
 
+#if KASAN
+#define MAX_ZONES       512
+#else /* !KASAN */
 #define MAX_ZONES       320
+#endif/* !KASAN */
 struct zone             zone_array[MAX_ZONES];
 
 /* Used to keep track of empty slots in the zone_array */
@@ -380,71 +426,73 @@ bitmap_t zone_empty_bitmap[BITMAP_LEN(MAX_ZONES)];
  * Or we can end up with multiple test zones (if a second zinit() comes through before zdestroy()),  which could lead us to
  * run out of zones.
  */
-decl_simple_lock_data(, zone_test_lock)
+decl_simple_lock_data(, zone_test_lock);
 static boolean_t zone_test_running = FALSE;
 static zone_t test_zone_ptr = NULL;
 #endif /* DEBUG || DEVELOPMENT */
 
-#define PAGE_METADATA_GET_ZINDEX(page_meta)                    \
+#define PAGE_METADATA_GET_ZINDEX(page_meta)                     \
        (page_meta->zindex)
 
-#define PAGE_METADATA_GET_ZONE(page_meta)                              \
+#define PAGE_METADATA_GET_ZONE(page_meta)                               \
        (&(zone_array[page_meta->zindex]))
 
-#define PAGE_METADATA_SET_ZINDEX(page_meta, index)             \
+#define PAGE_METADATA_SET_ZINDEX(page_meta, index)              \
        page_meta->zindex = (index);
 
 struct zone_page_metadata {
-       queue_chain_t           pages; /* linkage pointer for metadata lists */
+       queue_chain_t           pages; /* linkage pointer for metadata lists */
 
        /* Union for maintaining start of element free list and real metadata (for multipage allocations) */
        union {
-               /* 
-                * The start of the freelist can be maintained as a 32-bit offset instead of a pointer because 
-                * the free elements would be at max ZONE_MAX_ALLOC_SIZE bytes away from the metadata. Offset 
+               /*
+                * The start of the freelist can be maintained as a 32-bit offset instead of a pointer because
+                * the free elements would be at max ZONE_MAX_ALLOC_SIZE bytes away from the metadata. Offset
                 * from start of the allocation chunk to free element list head.
                 */
-               uint32_t                freelist_offset;
-               /* 
-                * This field is used to lookup the real metadata for multipage allocations, where we mark the 
-                * metadata for all pages except the first as "fake" metadata using MULTIPAGE_METADATA_MAGIC. 
+               uint32_t                freelist_offset;
+               /*
+                * This field is used to lookup the real metadata for multipage allocations, where we mark the
+                * metadata for all pages except the first as "fake" metadata using MULTIPAGE_METADATA_MAGIC.
                 * Offset from this fake metadata to real metadata of allocation chunk (-ve offset).
                 */
-               uint32_t                real_metadata_offset;  
+               uint32_t                real_metadata_offset;
        };
 
-       /* 
-        * For the first page in the allocation chunk, this represents the total number of free elements in 
-        * the chunk. 
+       /*
+        * For the first page in the allocation chunk, this represents the total number of free elements in
+        * the chunk.
         */
-       uint16_t                        free_count;
-       unsigned                        zindex     : ZINDEX_BITS;    /* Zone index within the zone_array */
-       unsigned                        page_count : PAGECOUNT_BITS; /* Count of pages within the allocation chunk */
+       uint16_t                        free_count;
+       unsigned                        zindex     : ZINDEX_BITS;    /* Zone index within the zone_array */
+       unsigned                        page_count : PAGECOUNT_BITS; /* Count of pages within the allocation chunk */
 };
 
 /* Macro to get page index (within zone_map) of page containing element */
-#define PAGE_INDEX_FOR_ELEMENT(element)                        \
+#define PAGE_INDEX_FOR_ELEMENT(element)                         \
        (((vm_offset_t)trunc_page(element) - zone_map_min_address) / PAGE_SIZE)
 
 /* Macro to get metadata structure given a page index in zone_map */
-#define PAGE_METADATA_FOR_PAGE_INDEX(index)                    \
+#define PAGE_METADATA_FOR_PAGE_INDEX(index)                     \
        (zone_metadata_region_min + ((index) * sizeof(struct zone_page_metadata)))
 
 /* Macro to get index (within zone_map) for given metadata */
-#define PAGE_INDEX_FOR_METADATA(page_meta)                     \
+#define PAGE_INDEX_FOR_METADATA(page_meta)                      \
        (((vm_offset_t)page_meta - zone_metadata_region_min) / sizeof(struct zone_page_metadata))
 
 /* Macro to get page for given page index in zone_map */
-#define PAGE_FOR_PAGE_INDEX(index)                             \
-       (zone_map_min_address + (PAGE_SIZE * (index))) 
+#define PAGE_FOR_PAGE_INDEX(index)                              \
+       (zone_map_min_address + (PAGE_SIZE * (index)))
 
 /* Macro to get the actual metadata for a given address */
-#define PAGE_METADATA_FOR_ELEMENT(element)             \
+#define PAGE_METADATA_FOR_ELEMENT(element)              \
        (struct zone_page_metadata *)(PAGE_METADATA_FOR_PAGE_INDEX(PAGE_INDEX_FOR_ELEMENT(element)))
 
 /* Magic value to indicate empty element free list */
-#define PAGE_METADATA_EMPTY_FREELIST           ((uint32_t)(~0))
+#define PAGE_METADATA_EMPTY_FREELIST            ((uint32_t)(~0))
 
+vm_map_copy_t create_vm_map_copy(vm_offset_t start_addr, vm_size_t total_size, vm_size_t used_size);
+boolean_t get_zone_info(zone_t z, mach_zone_name_t *zn, mach_zone_info_t *zi);
 boolean_t is_zone_map_nearing_exhaustion(void);
 extern void vm_pageout_garbage_collect(int collect);
 
@@ -452,13 +500,14 @@ static inline void *
 page_metadata_get_freelist(struct zone_page_metadata *page_meta)
 {
        assert(PAGE_METADATA_GET_ZINDEX(page_meta) != MULTIPAGE_METADATA_MAGIC);
-       if (page_meta->freelist_offset == PAGE_METADATA_EMPTY_FREELIST)
+       if (page_meta->freelist_offset == PAGE_METADATA_EMPTY_FREELIST) {
                return NULL;
-       else {
-               if (from_zone_map(page_meta, sizeof(struct zone_page_metadata)))
+       else {
+               if (from_zone_map(page_meta, sizeof(struct zone_page_metadata))) {
                        return (void *)(PAGE_FOR_PAGE_INDEX(PAGE_INDEX_FOR_METADATA(page_meta)) + page_meta->freelist_offset);
-               else
+               } else {
                        return (void *)((vm_offset_t)page_meta + page_meta->freelist_offset);
+               }
        }
 }
 
@@ -466,13 +515,14 @@ static inline void
 page_metadata_set_freelist(struct zone_page_metadata *page_meta, void *addr)
 {
        assert(PAGE_METADATA_GET_ZINDEX(page_meta) != MULTIPAGE_METADATA_MAGIC);
-       if (addr == NULL)
+       if (addr == NULL) {
                page_meta->freelist_offset = PAGE_METADATA_EMPTY_FREELIST;
-       else {
-               if (from_zone_map(page_meta, sizeof(struct zone_page_metadata)))
+       else {
+               if (from_zone_map(page_meta, sizeof(struct zone_page_metadata))) {
                        page_meta->freelist_offset = (uint32_t)((vm_offset_t)(addr) - PAGE_FOR_PAGE_INDEX(PAGE_INDEX_FOR_METADATA(page_meta)));
-               else
+               } else {
                        page_meta->freelist_offset = (uint32_t)((vm_offset_t)(addr) - (vm_offset_t)page_meta);
+               }
        }
 }
 
@@ -483,46 +533,55 @@ page_metadata_get_realmeta(struct zone_page_metadata *page_meta)
        return (struct zone_page_metadata *)((vm_offset_t)page_meta - page_meta->real_metadata_offset);
 }
 
-static inline void 
+static inline void
 page_metadata_set_realmeta(struct zone_page_metadata *page_meta, struct zone_page_metadata *real_meta)
 {
-               assert(PAGE_METADATA_GET_ZINDEX(page_meta) == MULTIPAGE_METADATA_MAGIC);
-               assert(PAGE_METADATA_GET_ZINDEX(real_meta) != MULTIPAGE_METADATA_MAGIC);
-               assert((vm_offset_t)page_meta > (vm_offset_t)real_meta);
-               vm_offset_t offset = (vm_offset_t)page_meta - (vm_offset_t)real_meta;
-               assert(offset <= UINT32_MAX);
-               page_meta->real_metadata_offset = (uint32_t)offset;
+       assert(PAGE_METADATA_GET_ZINDEX(page_meta) == MULTIPAGE_METADATA_MAGIC);
+       assert(PAGE_METADATA_GET_ZINDEX(real_meta) != MULTIPAGE_METADATA_MAGIC);
+       assert((vm_offset_t)page_meta > (vm_offset_t)real_meta);
+       vm_offset_t offset = (vm_offset_t)page_meta - (vm_offset_t)real_meta;
+       assert(offset <= UINT32_MAX);
+       page_meta->real_metadata_offset = (uint32_t)offset;
 }
 
 /* The backup pointer is stored in the last pointer-sized location in an element. */
 static inline vm_offset_t *
 get_backup_ptr(vm_size_t  elem_size,
-               vm_offset_t *element)
+    vm_offset_t *element)
 {
        return (vm_offset_t *) ((vm_offset_t)element + elem_size - sizeof(vm_offset_t));
 }
 
-/* 
+/*
  * Routine to populate a page backing metadata in the zone_metadata_region.
- * Must be called without the zone lock held as it might potentially block. 
+ * Must be called without the zone lock held as it might potentially block.
  */
 static inline void
-zone_populate_metadata_page(struct zone_page_metadata *page_meta) 
+zone_populate_metadata_page(struct zone_page_metadata *page_meta)
 {
        vm_offset_t page_metadata_begin = trunc_page(page_meta);
        vm_offset_t page_metadata_end = trunc_page((vm_offset_t)page_meta + sizeof(struct zone_page_metadata));
-       
-       for(;page_metadata_begin <= page_metadata_end; page_metadata_begin += PAGE_SIZE) {
-               if (pmap_find_phys(kernel_pmap, (vm_map_address_t)page_metadata_begin))
+
+       for (; page_metadata_begin <= page_metadata_end; page_metadata_begin += PAGE_SIZE) {
+#if !KASAN
+               /*
+                * This can race with another thread doing a populate on the same metadata
+                * page, where we see an updated pmap but unmapped KASan shadow, causing a
+                * fault in the shadow when we first access the metadata page. Avoid this
+                * by always synchronizing on the zone_metadata_region lock with KASan.
+                */
+               if (pmap_find_phys(kernel_pmap, (vm_map_address_t)page_metadata_begin)) {
                        continue;
+               }
+#endif
                /* All updates to the zone_metadata_region are done under the zone_metadata_region_lck */
                lck_mtx_lock(&zone_metadata_region_lck);
                if (0 == pmap_find_phys(kernel_pmap, (vm_map_address_t)page_metadata_begin)) {
-                       kern_return_t __unused ret = kernel_memory_populate(zone_map,
-                                      page_metadata_begin,
-                                      PAGE_SIZE,
-                                      KMA_KOBJECT,
-                                      VM_KERN_MEMORY_OSFMK);
+                       kern_return_t __assert_only ret = kernel_memory_populate(zone_map,
+                           page_metadata_begin,
+                           PAGE_SIZE,
+                           KMA_KOBJECT,
+                           VM_KERN_MEMORY_OSFMK);
 
                        /* should not fail with the given arguments */
                        assert(ret == KERN_SUCCESS);
@@ -535,13 +594,13 @@ zone_populate_metadata_page(struct zone_page_metadata *page_meta)
 static inline uint16_t
 get_metadata_alloc_count(struct zone_page_metadata *page_meta)
 {
-               assert(PAGE_METADATA_GET_ZINDEX(page_meta) != MULTIPAGE_METADATA_MAGIC);
-               struct zone *z = PAGE_METADATA_GET_ZONE(page_meta);
-               return ((page_meta->page_count * PAGE_SIZE) / z->elem_size);
+       assert(PAGE_METADATA_GET_ZINDEX(page_meta) != MULTIPAGE_METADATA_MAGIC);
+       struct zone *z = PAGE_METADATA_GET_ZONE(page_meta);
+       return (page_meta->page_count * PAGE_SIZE) / z->elem_size;
 }
 
-/* 
- * Routine to lookup metadata for any given address. 
+/*
+ * Routine to lookup metadata for any given address.
  * If init is marked as TRUE, this should be called without holding the zone lock
  * since the initialization might block.
  */
@@ -550,26 +609,54 @@ get_zone_page_metadata(struct zone_free_element *element, boolean_t init)
 {
        struct zone_page_metadata *page_meta = 0;
 
-       if (from_zone_map(element, sizeof(struct zone_free_element))) { 
+       if (from_zone_map(element, sizeof(struct zone_free_element))) {
                page_meta = (struct zone_page_metadata *)(PAGE_METADATA_FOR_ELEMENT(element));
-               if (init)
+               if (init) {
                        zone_populate_metadata_page(page_meta);
+               }
        } else {
                page_meta = (struct zone_page_metadata *)(trunc_page((vm_offset_t)element));
        }
-       if (init)
-               __nosan_bzero((char *)page_meta, sizeof(struct zone_page_metadata));
-       return ((PAGE_METADATA_GET_ZINDEX(page_meta) != MULTIPAGE_METADATA_MAGIC) ? page_meta : page_metadata_get_realmeta(page_meta));
+       if (init) {
+               bzero((char *)page_meta, sizeof(struct zone_page_metadata));
+       }
+       return (PAGE_METADATA_GET_ZINDEX(page_meta) != MULTIPAGE_METADATA_MAGIC) ? page_meta : page_metadata_get_realmeta(page_meta);
 }
 
 /* Routine to get the page for a given metadata */
 static inline vm_offset_t
 get_zone_page(struct zone_page_metadata *page_meta)
 {
-       if (from_zone_map(page_meta, sizeof(struct zone_page_metadata)))
+       if (from_zone_map(page_meta, sizeof(struct zone_page_metadata))) {
                return (vm_offset_t)(PAGE_FOR_PAGE_INDEX(PAGE_INDEX_FOR_METADATA(page_meta)));
-       else
+       } else {
                return (vm_offset_t)(trunc_page(page_meta));
+       }
+}
+
+/*
+ * Routine to panic if a pointer is not mapped to an expected zone.
+ * This can be used as a means of pinning an object to the zone it is expected
+ * to be a part of.  Causes a panic if the address does not belong to any
+ * specified zone, does not belong to any zone, has been freed and therefore
+ * unmapped from the zone, or the pointer contains an uninitialized value that
+ * does not belong to any zone.
+ */
+
+void
+zone_require(void *addr, zone_t expected_zone)
+{
+       struct zone *src_zone = NULL;
+       struct zone_page_metadata *page_meta = get_zone_page_metadata((struct zone_free_element *)addr, FALSE);
+
+       src_zone = PAGE_METADATA_GET_ZONE(page_meta);
+       if (__improbable(src_zone == NULL)) {
+               panic("Address not in a zone for zone_require check (addr: %p)", addr);
+       }
+
+       if (__improbable(src_zone != expected_zone)) {
+               panic("Address not in expected zone for zone_require check (addr: %p, zone: %s)", addr, src_zone->zone_name);
+       }
 }
 
 /*
@@ -590,14 +677,14 @@ get_zone_page(struct zone_page_metadata *page_meta)
 // pointer to the tag for an element
 #define ZTAG(zone, element)                                     \
     ({                                                          \
-        vm_tag_t * result;                                      \
-        if ((zone)->tags_inline) {                              \
-            result = (vm_tag_t *) ZTAGBASE((zone), (element));  \
-            if ((page_mask & element) >= (zone)->elem_size) result++;    \
-        } else {                                                \
-            result =  &((vm_tag_t *)zone_tags_min)[ZTAGBASE((zone), (element))[0] + ((element) & page_mask) / (zone)->elem_size];   \
-        }                                                       \
-        result;                                                 \
+       vm_tag_t * result;                                      \
+       if ((zone)->tags_inline) {                              \
+           result = (vm_tag_t *) ZTAGBASE((zone), (element));  \
+           if ((page_mask & element) >= (zone)->elem_size) result++;    \
+       } else {                                                \
+           result =  &((vm_tag_t *)zone_tags_min)[ZTAGBASE((zone), (element))[0] + ((element) & page_mask) / (zone)->elem_size];   \
+       }                                                       \
+       result;                                                 \
     })
 
 
@@ -613,21 +700,19 @@ static vm_map_t     zone_tags_map;
 
 // simple heap allocator for allocating the tags for new memory
 
-decl_lck_mtx_data(,ztLock)    /* heap lock */
-enum
-{
-    ztFreeIndexCount = 8,
-    ztFreeIndexMax   = (ztFreeIndexCount - 1),
-    ztTagsPerBlock   = 4
+decl_lck_mtx_data(, ztLock);    /* heap lock */
+enum{
+       ztFreeIndexCount = 8,
+       ztFreeIndexMax   = (ztFreeIndexCount - 1),
+       ztTagsPerBlock   = 4
 };
 
-struct ztBlock
-{
+struct ztBlock {
 #if __LITTLE_ENDIAN__
-    uint64_t free:1,
-             next:21,
-             prev:21,
-             size:21;
+       uint64_t free:1,
+           next:21,
+           prev:21,
+           size:21;
 #else
 // ztBlock needs free bit least significant
 #error !__LITTLE_ENDIAN__
@@ -642,54 +727,56 @@ static uint32_t  ztBlocksFree;
 static uint32_t
 ztLog2up(uint32_t size)
 {
-    if (1 == size) size = 0;
-    else size = 32 - __builtin_clz(size - 1);
-    return (size);
+       if (1 == size) {
+               size = 0;
+       } else {
+               size = 32 - __builtin_clz(size - 1);
+       }
+       return size;
 }
 
 static uint32_t
 ztLog2down(uint32_t size)
 {
-    size = 31 - __builtin_clz(size);
-    return (size);
+       size = 31 - __builtin_clz(size);
+       return size;
 }
 
 static void
 ztFault(vm_map_t map, const void * address, size_t size, uint32_t flags)
 {
-    vm_map_offset_t addr = (vm_map_offset_t) address;
-    vm_map_offset_t page, end;
-
-    page = trunc_page(addr);
-    end  = round_page(addr + size);
-
-    for (; page < end; page += page_size)
-    {
-        if (!pmap_find_phys(kernel_pmap, page))
-        {
-            kern_return_t __unused
-            ret = kernel_memory_populate(map, page, PAGE_SIZE,
-                                         KMA_KOBJECT | flags, VM_KERN_MEMORY_DIAG);
-            assert(ret == KERN_SUCCESS);
-        }
-    }
+       vm_map_offset_t addr = (vm_map_offset_t) address;
+       vm_map_offset_t page, end;
+
+       page = trunc_page(addr);
+       end  = round_page(addr + size);
+
+       for (; page < end; page += page_size) {
+               if (!pmap_find_phys(kernel_pmap, page)) {
+                       kern_return_t __unused
+                       ret = kernel_memory_populate(map, page, PAGE_SIZE,
+                           KMA_KOBJECT | flags, VM_KERN_MEMORY_DIAG);
+                       assert(ret == KERN_SUCCESS);
+               }
+       }
 }
 
 static boolean_t
 ztPresent(const void * address, size_t size)
 {
-    vm_map_offset_t addr = (vm_map_offset_t) address;
-    vm_map_offset_t page, end;
-    boolean_t       result;
-
-    page = trunc_page(addr);
-    end  = round_page(addr + size);
-    for (result = TRUE; (page < end); page += page_size)
-    {
-        result = pmap_find_phys(kernel_pmap, page);
-        if (!result) break;
-    }
-    return (result);
+       vm_map_offset_t addr = (vm_map_offset_t) address;
+       vm_map_offset_t page, end;
+       boolean_t       result;
+
+       page = trunc_page(addr);
+       end  = round_page(addr + size);
+       for (result = TRUE; (page < end); page += page_size) {
+               result = pmap_find_phys(kernel_pmap, page);
+               if (!result) {
+                       break;
+               }
+       }
+       return result;
 }
 
 
@@ -698,40 +785,43 @@ ztDump(boolean_t sanity);
 void __unused
 ztDump(boolean_t sanity)
 {
-    uint32_t q, cq, p;
-
-    for (q = 0; q <= ztFreeIndexMax; q++)
-    {
-        p = q;
-        do
-        {
-            if (sanity)
-            {
-                cq = ztLog2down(ztBlocks[p].size);
-                if (cq > ztFreeIndexMax) cq = ztFreeIndexMax;
-                if (!ztBlocks[p].free
-                    || ((p != q) && (q != cq))
-                    || (ztBlocks[ztBlocks[p].next].prev != p)
-                    || (ztBlocks[ztBlocks[p].prev].next != p))
-                {
-                    kprintf("zterror at %d", p);
-                    ztDump(FALSE);
-                    kprintf("zterror at %d", p);
-                    assert(FALSE);
-                }
-                continue;
-            }
-            kprintf("zt[%03d]%c %d, %d, %d\n",
-                    p, ztBlocks[p].free ? 'F' : 'A',
-                    ztBlocks[p].next, ztBlocks[p].prev,
-                    ztBlocks[p].size);
-            p = ztBlocks[p].next;
-            if (p == q) break;
-        }
-        while (p != q);
-        if (!sanity) printf("\n");
-    }
-    if (!sanity) printf("-----------------------\n");
+       uint32_t q, cq, p;
+
+       for (q = 0; q <= ztFreeIndexMax; q++) {
+               p = q;
+               do{
+                       if (sanity) {
+                               cq = ztLog2down(ztBlocks[p].size);
+                               if (cq > ztFreeIndexMax) {
+                                       cq = ztFreeIndexMax;
+                               }
+                               if (!ztBlocks[p].free
+                                   || ((p != q) && (q != cq))
+                                   || (ztBlocks[ztBlocks[p].next].prev != p)
+                                   || (ztBlocks[ztBlocks[p].prev].next != p)) {
+                                       kprintf("zterror at %d", p);
+                                       ztDump(FALSE);
+                                       kprintf("zterror at %d", p);
+                                       assert(FALSE);
+                               }
+                               continue;
+                       }
+                       kprintf("zt[%03d]%c %d, %d, %d\n",
+                           p, ztBlocks[p].free ? 'F' : 'A',
+                           ztBlocks[p].next, ztBlocks[p].prev,
+                           ztBlocks[p].size);
+                       p = ztBlocks[p].next;
+                       if (p == q) {
+                               break;
+                       }
+               }while (p != q);
+               if (!sanity) {
+                       printf("\n");
+               }
+       }
+       if (!sanity) {
+               printf("-----------------------\n");
+       }
 }
 
 
@@ -743,254 +833,267 @@ ztDump(boolean_t sanity)
 static void
 ztFree(zone_t zone __unused, uint32_t index, uint32_t count)
 {
-    uint32_t q, w, p, size, merge;
-
-    assert(count);
-    ztBlocksFree += count;
-
-    // merge with preceding
-    merge = (index + count);
-    if ((merge < ztBlocksCount)
-        && ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
-        && ztBlocks[merge].free)
-    {
-        ZTBDEQ(merge);
-        count += ztBlocks[merge].size;
-    }
-
-    // merge with following
-    merge = (index - 1);
-    if ((merge > ztFreeIndexMax)
-        && ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
-        && ztBlocks[merge].free)
-    {
-        size = ztBlocks[merge].size;
-        count += size;
-        index -= size;
-        ZTBDEQ(index);
-    }
-
-    q = ztLog2down(count);
-    if (q > ztFreeIndexMax) q = ztFreeIndexMax;
-    w = q;
-    // queue in order of size
-    while (TRUE)
-    {
-        p = ztBlocks[w].next;
-        if (p == q) break;
-        if (ztBlocks[p].size >= count) break;
-        w = p;
-    }
-    ztBlocks[p].prev = index;
-    ztBlocks[w].next = index;
-
-    // fault in first
-    ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
-
-    // mark first & last with free flag and size
-    ztBlocks[index].free = TRUE;
-    ztBlocks[index].size = count;
-    ztBlocks[index].prev = w;
-    ztBlocks[index].next = p;
-    if (count > 1)
-    {
-        index += (count - 1);
-        // fault in last
-        ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
-        ztBlocks[index].free = TRUE;
-        ztBlocks[index].size = count;
-    }
+       uint32_t q, w, p, size, merge;
+
+       assert(count);
+       ztBlocksFree += count;
+
+       // merge with preceding
+       merge = (index + count);
+       if ((merge < ztBlocksCount)
+           && ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
+           && ztBlocks[merge].free) {
+               ZTBDEQ(merge);
+               count += ztBlocks[merge].size;
+       }
+
+       // merge with following
+       merge = (index - 1);
+       if ((merge > ztFreeIndexMax)
+           && ztPresent(&ztBlocks[merge], sizeof(ztBlocks[merge]))
+           && ztBlocks[merge].free) {
+               size = ztBlocks[merge].size;
+               count += size;
+               index -= size;
+               ZTBDEQ(index);
+       }
+
+       q = ztLog2down(count);
+       if (q > ztFreeIndexMax) {
+               q = ztFreeIndexMax;
+       }
+       w = q;
+       // queue in order of size
+       while (TRUE) {
+               p = ztBlocks[w].next;
+               if (p == q) {
+                       break;
+               }
+               if (ztBlocks[p].size >= count) {
+                       break;
+               }
+               w = p;
+       }
+       ztBlocks[p].prev = index;
+       ztBlocks[w].next = index;
+
+       // fault in first
+       ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
+
+       // mark first & last with free flag and size
+       ztBlocks[index].free = TRUE;
+       ztBlocks[index].size = count;
+       ztBlocks[index].prev = w;
+       ztBlocks[index].next = p;
+       if (count > 1) {
+               index += (count - 1);
+               // fault in last
+               ztFault(zone_tags_map, &ztBlocks[index], sizeof(ztBlocks[index]), 0);
+               ztBlocks[index].free = TRUE;
+               ztBlocks[index].size = count;
+       }
 }
 
 static uint32_t
 ztAlloc(zone_t zone, uint32_t count)
 {
-    uint32_t q, w, p, leftover;
-
-    assert(count);
-
-    q = ztLog2up(count);
-    if (q > ztFreeIndexMax) q = ztFreeIndexMax;
-    do
-    {
-        w = q;
-        while (TRUE)
-        {
-            p = ztBlocks[w].next;
-            if (p == q) break;
-            if (ztBlocks[p].size >= count)
-            {
-                // dequeue, mark both ends allocated
-                ztBlocks[w].next = ztBlocks[p].next;
-                ztBlocks[ztBlocks[p].next].prev = w;
-                ztBlocks[p].free = FALSE;
-                ztBlocksFree -= ztBlocks[p].size;
-                if (ztBlocks[p].size > 1) ztBlocks[p + ztBlocks[p].size - 1].free = FALSE;
-
-                // fault all the allocation
-                ztFault(zone_tags_map, &ztBlocks[p], count * sizeof(ztBlocks[p]), 0);
-                // mark last as allocated
-                if (count > 1) ztBlocks[p + count - 1].free = FALSE;
-                // free remainder
-                leftover = ztBlocks[p].size - count;
-                if (leftover) ztFree(zone, p + ztBlocks[p].size - leftover, leftover);
-
-                return (p);
-            }
-            w = p;
-        }
-        q++;
-    }
-    while (q <= ztFreeIndexMax);
-
-    return (-1U);
+       uint32_t q, w, p, leftover;
+
+       assert(count);
+
+       q = ztLog2up(count);
+       if (q > ztFreeIndexMax) {
+               q = ztFreeIndexMax;
+       }
+       do{
+               w = q;
+               while (TRUE) {
+                       p = ztBlocks[w].next;
+                       if (p == q) {
+                               break;
+                       }
+                       if (ztBlocks[p].size >= count) {
+                               // dequeue, mark both ends allocated
+                               ztBlocks[w].next = ztBlocks[p].next;
+                               ztBlocks[ztBlocks[p].next].prev = w;
+                               ztBlocks[p].free = FALSE;
+                               ztBlocksFree -= ztBlocks[p].size;
+                               if (ztBlocks[p].size > 1) {
+                                       ztBlocks[p + ztBlocks[p].size - 1].free = FALSE;
+                               }
+
+                               // fault all the allocation
+                               ztFault(zone_tags_map, &ztBlocks[p], count * sizeof(ztBlocks[p]), 0);
+                               // mark last as allocated
+                               if (count > 1) {
+                                       ztBlocks[p + count - 1].free = FALSE;
+                               }
+                               // free remainder
+                               leftover = ztBlocks[p].size - count;
+                               if (leftover) {
+                                       ztFree(zone, p + ztBlocks[p].size - leftover, leftover);
+                               }
+
+                               return p;
+                       }
+                       w = p;
+               }
+               q++;
+       }while (q <= ztFreeIndexMax);
+
+       return -1U;
 }
 
 static void
 ztInit(vm_size_t max_zonemap_size, lck_grp_t * group)
 {
-    kern_return_t         ret;
-    vm_map_kernel_flags_t vmk_flags;
-    uint32_t              idx;
-
-    lck_mtx_init(&ztLock, group, LCK_ATTR_NULL);
-
-    // allocate submaps VM_KERN_MEMORY_DIAG
-
-    zone_tagbase_map_size = atop(max_zonemap_size) * sizeof(uint32_t);
-    vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
-    vmk_flags.vmkf_permanent = TRUE;
-    ret = kmem_suballoc(kernel_map, &zone_tagbase_min, zone_tagbase_map_size,
-                   FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
-                   &zone_tagbase_map);
-
-    if (ret != KERN_SUCCESS) panic("zone_init: kmem_suballoc failed");
-    zone_tagbase_max = zone_tagbase_min + round_page(zone_tagbase_map_size);
-
-    zone_tags_map_size = 2048*1024 * sizeof(vm_tag_t);
-    vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
-    vmk_flags.vmkf_permanent = TRUE;
-    ret = kmem_suballoc(kernel_map, &zone_tags_min, zone_tags_map_size,
-                   FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
-                   &zone_tags_map);
-
-    if (ret != KERN_SUCCESS) panic("zone_init: kmem_suballoc failed");
-    zone_tags_max = zone_tags_min + round_page(zone_tags_map_size);
-
-    ztBlocks = (ztBlock *) zone_tags_min;
-    ztBlocksCount = (uint32_t)(zone_tags_map_size / sizeof(ztBlock));
-
-    // initialize the qheads
-    lck_mtx_lock(&ztLock);
-
-    ztFault(zone_tags_map, &ztBlocks[0], sizeof(ztBlocks[0]), 0);
-    for (idx = 0; idx < ztFreeIndexCount; idx++)
-    {
-        ztBlocks[idx].free = TRUE;
-        ztBlocks[idx].next = idx;
-        ztBlocks[idx].prev = idx;
-        ztBlocks[idx].size = 0;
-    }
-    // free remaining space
-    ztFree(NULL, ztFreeIndexCount, ztBlocksCount - ztFreeIndexCount);
-
-    lck_mtx_unlock(&ztLock);
+       kern_return_t         ret;
+       vm_map_kernel_flags_t vmk_flags;
+       uint32_t              idx;
+
+       lck_mtx_init(&ztLock, group, LCK_ATTR_NULL);
+
+       // allocate submaps VM_KERN_MEMORY_DIAG
+
+       zone_tagbase_map_size = atop(max_zonemap_size) * sizeof(uint32_t);
+       vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
+       vmk_flags.vmkf_permanent = TRUE;
+       ret = kmem_suballoc(kernel_map, &zone_tagbase_min, zone_tagbase_map_size,
+           FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
+           &zone_tagbase_map);
+
+       if (ret != KERN_SUCCESS) {
+               panic("zone_init: kmem_suballoc failed");
+       }
+       zone_tagbase_max = zone_tagbase_min + round_page(zone_tagbase_map_size);
+
+       zone_tags_map_size = 2048 * 1024 * sizeof(vm_tag_t);
+       vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
+       vmk_flags.vmkf_permanent = TRUE;
+       ret = kmem_suballoc(kernel_map, &zone_tags_min, zone_tags_map_size,
+           FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_DIAG,
+           &zone_tags_map);
+
+       if (ret != KERN_SUCCESS) {
+               panic("zone_init: kmem_suballoc failed");
+       }
+       zone_tags_max = zone_tags_min + round_page(zone_tags_map_size);
+
+       ztBlocks = (ztBlock *) zone_tags_min;
+       ztBlocksCount = (uint32_t)(zone_tags_map_size / sizeof(ztBlock));
+
+       // initialize the qheads
+       lck_mtx_lock(&ztLock);
+
+       ztFault(zone_tags_map, &ztBlocks[0], sizeof(ztBlocks[0]), 0);
+       for (idx = 0; idx < ztFreeIndexCount; idx++) {
+               ztBlocks[idx].free = TRUE;
+               ztBlocks[idx].next = idx;
+               ztBlocks[idx].prev = idx;
+               ztBlocks[idx].size = 0;
+       }
+       // free remaining space
+       ztFree(NULL, ztFreeIndexCount, ztBlocksCount - ztFreeIndexCount);
+
+       lck_mtx_unlock(&ztLock);
 }
 
 static void
 ztMemoryAdd(zone_t zone, vm_offset_t mem, vm_size_t size)
 {
-    uint32_t * tagbase;
-    uint32_t   count, block, blocks, idx;
-    size_t     pages;
-
-    pages = atop(size);
-    tagbase = ZTAGBASE(zone, mem);
-
-    lck_mtx_lock(&ztLock);
-
-    // fault tagbase
-    ztFault(zone_tagbase_map, tagbase, pages * sizeof(uint32_t), 0);
-
-    if (!zone->tags_inline)
-    {
-        // allocate tags
-        count = (uint32_t)(size / zone->elem_size);
-        blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
-        block = ztAlloc(zone, blocks);
-        if (-1U == block) ztDump(false);
-        assert(-1U != block);
-    }
-
-    lck_mtx_unlock(&ztLock);
-
-    if (!zone->tags_inline)
-    {
-        // set tag base for each page
-        block *= ztTagsPerBlock;
-        for (idx = 0; idx < pages; idx++)
-        {
-            tagbase[idx] = block + (uint32_t)((ptoa(idx) + (zone->elem_size - 1)) / zone->elem_size);
-        }
-    }
+       uint32_t * tagbase;
+       uint32_t   count, block, blocks, idx;
+       size_t     pages;
+
+       pages = atop(size);
+       tagbase = ZTAGBASE(zone, mem);
+
+       lck_mtx_lock(&ztLock);
+
+       // fault tagbase
+       ztFault(zone_tagbase_map, tagbase, pages * sizeof(uint32_t), 0);
+
+       if (!zone->tags_inline) {
+               // allocate tags
+               count = (uint32_t)(size / zone->elem_size);
+               blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
+               block = ztAlloc(zone, blocks);
+               if (-1U == block) {
+                       ztDump(false);
+               }
+               assert(-1U != block);
+       }
+
+       lck_mtx_unlock(&ztLock);
+
+       if (!zone->tags_inline) {
+               // set tag base for each page
+               block *= ztTagsPerBlock;
+               for (idx = 0; idx < pages; idx++) {
+                       tagbase[idx] = block + (uint32_t)((ptoa(idx) + (zone->elem_size - 1)) / zone->elem_size);
+               }
+       }
 }
 
 static void
 ztMemoryRemove(zone_t zone, vm_offset_t mem, vm_size_t size)
 {
-    uint32_t * tagbase;
-    uint32_t   count, block, blocks, idx;
-    size_t     pages;
-
-    // set tag base for each page
-    pages = atop(size);
-    tagbase = ZTAGBASE(zone, mem);
-    block = tagbase[0];
-    for (idx = 0; idx < pages; idx++)
-    {
-        tagbase[idx] = 0xFFFFFFFF;
-    }
-
-    lck_mtx_lock(&ztLock);
-    if (!zone->tags_inline)
-    {
-        count = (uint32_t)(size / zone->elem_size);
-        blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
-        assert(block != 0xFFFFFFFF);
-        block /= ztTagsPerBlock;
-        ztFree(NULL /* zone is unlocked */, block, blocks);
-    }
-
-    lck_mtx_unlock(&ztLock);
+       uint32_t * tagbase;
+       uint32_t   count, block, blocks, idx;
+       size_t     pages;
+
+       // set tag base for each page
+       pages = atop(size);
+       tagbase = ZTAGBASE(zone, mem);
+       block = tagbase[0];
+       for (idx = 0; idx < pages; idx++) {
+               tagbase[idx] = 0xFFFFFFFF;
+       }
+
+       lck_mtx_lock(&ztLock);
+       if (!zone->tags_inline) {
+               count = (uint32_t)(size / zone->elem_size);
+               blocks = ((count + ztTagsPerBlock - 1) / ztTagsPerBlock);
+               assert(block != 0xFFFFFFFF);
+               block /= ztTagsPerBlock;
+               ztFree(NULL /* zone is unlocked */, block, blocks);
+       }
+
+       lck_mtx_unlock(&ztLock);
 }
 
 uint32_t
 zone_index_from_tag_index(uint32_t tag_zone_index, vm_size_t * elem_size)
 {
-    zone_t z;
-    uint32_t idx;
+       zone_t z;
+       uint32_t idx;
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
 
-    for (idx = 0; idx < num_zones; idx++)
-    {
+       for (idx = 0; idx < num_zones; idx++) {
                z = &(zone_array[idx]);
-               if (!z->tags) continue;
-           if (tag_zone_index != z->tag_zone_index) continue;
-           *elem_size = z->elem_size;
-           break;
-    }
+               if (!z->tags) {
+                       continue;
+               }
+               if (tag_zone_index != z->tag_zone_index) {
+                       continue;
+               }
+               *elem_size = z->elem_size;
+               break;
+       }
 
-    simple_unlock(&all_zones_lock);
+       simple_unlock(&all_zones_lock);
 
-    if (idx == num_zones) idx = -1U;
+       if (idx == num_zones) {
+               idx = -1U;
+       }
 
-    return (idx);
+       return idx;
 }
 
 #endif /* VM_MAX_TAG_ZONES */
 
-/* Routine to get the size of a zone allocated address. If the address doesnt belong to the 
+/* Routine to get the size of a zone allocated address. If the address doesnt belong to the
  * zone_map, returns 0.
  */
 vm_size_t
@@ -1003,7 +1106,7 @@ zone_element_size(void *addr, zone_t *z)
                if (z) {
                        *z = src_zone;
                }
-               return (src_zone->elem_size);
+               return src_zone->elem_size;
        } else {
 #if CONFIG_GZALLOC
                vm_size_t gzsize;
@@ -1029,9 +1132,9 @@ zone_element_info(void *addr, vm_tag_t * ptag)
                struct zone_page_metadata *page_meta = get_zone_page_metadata((struct zone_free_element *)addr, FALSE);
                src_zone = PAGE_METADATA_GET_ZONE(page_meta);
 #if VM_MAX_TAG_ZONES
-           if (__improbable(src_zone->tags)) {
+               if (__improbable(src_zone->tags)) {
                        tag = (ZTAG(src_zone, (vm_offset_t) addr)[0] >> 1);
-           }
+               }
 #endif /* VM_MAX_TAG_ZONES */
                size = src_zone->elem_size;
        } else {
@@ -1051,17 +1154,19 @@ zone_element_info(void *addr, vm_tag_t * ptag)
  * A pointer that doesn't satisfy these conditions indicates corruption
  */
 static inline boolean_t
-is_sane_zone_ptr(zone_t                zone,
-                 vm_offset_t   addr,
-                size_t         obj_size)
+is_sane_zone_ptr(zone_t         zone,
+    vm_offset_t    addr,
+    size_t         obj_size)
 {
        /*  Must be aligned to pointer boundary */
-       if (__improbable((addr & (sizeof(vm_offset_t) - 1)) != 0))
+       if (__improbable((addr & (sizeof(vm_offset_t) - 1)) != 0)) {
                return FALSE;
+       }
 
        /*  Must be a kernel address */
-       if (__improbable(!pmap_kernel_va(addr)))
+       if (__improbable(!pmap_kernel_va(addr))) {
                return FALSE;
+       }
 
        /*  Must be from zone map if the zone only uses memory from the zone_map */
        /*
@@ -1070,9 +1175,10 @@ is_sane_zone_ptr(zone_t          zone,
         */
        if (zone->collectable && !zone->allows_foreign) {
                /*  check if addr is from zone map */
-               if (addr                 >= zone_map_min_address &&
-                  (addr + obj_size - 1) <  zone_map_max_address )
+               if (addr >= zone_map_min_address &&
+                   (addr + obj_size - 1) < zone_map_max_address) {
                        return TRUE;
+               }
 
                return FALSE;
        }
@@ -1081,56 +1187,59 @@ is_sane_zone_ptr(zone_t         zone,
 }
 
 static inline boolean_t
-is_sane_zone_page_metadata(zone_t      zone,
-                          vm_offset_t  page_meta)
+is_sane_zone_page_metadata(zone_t       zone,
+    vm_offset_t  page_meta)
 {
        /* NULL page metadata structures are invalid */
-       if (page_meta == 0)
+       if (page_meta == 0) {
                return FALSE;
+       }
        return is_sane_zone_ptr(zone, page_meta, sizeof(struct zone_page_metadata));
 }
 
 static inline boolean_t
 is_sane_zone_element(zone_t      zone,
-                     vm_offset_t addr)
+    vm_offset_t addr)
 {
        /*  NULL is OK because it indicates the tail of the list */
-       if (addr == 0)
+       if (addr == 0) {
                return TRUE;
+       }
        return is_sane_zone_ptr(zone, addr, zone->elem_size);
 }
-       
+
 /* Someone wrote to freed memory. */
-static inline void /* noreturn */
+__dead2
+static inline void
 zone_element_was_modified_panic(zone_t        zone,
-                                vm_offset_t   element,
-                                vm_offset_t   found,
-                                vm_offset_t   expected,
-                                vm_offset_t   offset)
+    vm_offset_t   element,
+    vm_offset_t   found,
+    vm_offset_t   expected,
+    vm_offset_t   offset)
 {
        panic("a freed zone element has been modified in zone %s: expected %p but found %p, bits changed %p, at offset %d of %d in element %p, cookies %p %p",
-                        zone->zone_name,
-             (void *)   expected,
-             (void *)   found,
-             (void *)   (expected ^ found),
-             (uint32_t) offset,
-             (uint32_t) zone->elem_size,
-             (void *)   element,
-             (void *)   zp_nopoison_cookie,
-             (void *)   zp_poisoned_cookie);
+           zone->zone_name,
+           (void *)   expected,
+           (void *)   found,
+           (void *)   (expected ^ found),
+           (uint32_t) offset,
+           (uint32_t) zone->elem_size,
+           (void *)   element,
+           (void *)   zp_nopoison_cookie,
+           (void *)   zp_poisoned_cookie);
 }
 
 /*
  * The primary and backup pointers don't match.
  * Determine which one was likely the corrupted pointer, find out what it
  * probably should have been, and panic.
- * I would like to mark this as noreturn, but panic() isn't marked noreturn.
  */
-static void /* noreturn */
+__dead2
+static void
 backup_ptr_mismatch_panic(zone_t        zone,
-                          vm_offset_t   element,
-                          vm_offset_t   primary,
-                          vm_offset_t   backup)
+    vm_offset_t   element,
+    vm_offset_t   primary,
+    vm_offset_t   backup)
 {
        vm_offset_t likely_backup;
        vm_offset_t likely_primary;
@@ -1142,10 +1251,11 @@ backup_ptr_mismatch_panic(zone_t        zone,
 
 #if defined(__LP64__)
        /* We can inspect the tag in the upper bits for additional confirmation */
-       if ((backup & 0xFFFFFF0000000000) == 0xFACADE0000000000)
+       if ((backup & 0xFFFFFF0000000000) == 0xFACADE0000000000) {
                element_was_poisoned = TRUE;
-       else if ((backup & 0xFFFFFF0000000000) == 0xC0FFEE0000000000)
+       } else if ((backup & 0xFFFFFF0000000000) == 0xC0FFEE0000000000) {
                element_was_poisoned = FALSE;
+       }
 #endif
 
        if (element_was_poisoned) {
@@ -1157,14 +1267,16 @@ backup_ptr_mismatch_panic(zone_t        zone,
        }
 
        /* The primary is definitely the corrupted one */
-       if (!sane_primary && sane_backup)
+       if (!sane_primary && sane_backup) {
                zone_element_was_modified_panic(zone, element, primary, (likely_backup ^ zp_nopoison_cookie), 0);
+       }
 
        /* The backup is definitely the corrupted one */
-       if (sane_primary && !sane_backup)
+       if (sane_primary && !sane_backup) {
                zone_element_was_modified_panic(zone, element, backup,
-                                               (likely_primary ^ (element_was_poisoned ? zp_poisoned_cookie : zp_nopoison_cookie)),
-                                               zone->elem_size - sizeof(vm_offset_t));
+                   (likely_primary ^ (element_was_poisoned ? zp_poisoned_cookie : zp_nopoison_cookie)),
+                   zone->elem_size - sizeof(vm_offset_t));
+       }
 
        /*
         * Not sure which is the corrupted one.
@@ -1172,8 +1284,9 @@ backup_ptr_mismatch_panic(zone_t        zone,
         * ( (sane address) ^ (valid cookie) ), so we'll guess that the
         * primary pointer has been overwritten with a sane but incorrect address.
         */
-       if (sane_primary && sane_backup)
+       if (sane_primary && sane_backup) {
                zone_element_was_modified_panic(zone, element, primary, (likely_backup ^ zp_nopoison_cookie), 0);
+       }
 
        /* Neither are sane, so just guess. */
        zone_element_was_modified_panic(zone, element, primary, (likely_backup ^ zp_nopoison_cookie), 0);
@@ -1185,8 +1298,8 @@ backup_ptr_mismatch_panic(zone_t        zone,
  */
 static inline void
 free_to_zone(zone_t      zone,
-             vm_offset_t element,
-             boolean_t   poison)
+    vm_offset_t element,
+    boolean_t   poison)
 {
        vm_offset_t old_head;
        struct zone_page_metadata *page_meta;
@@ -1198,16 +1311,20 @@ free_to_zone(zone_t      zone,
        assert(PAGE_METADATA_GET_ZONE(page_meta) == zone);
        old_head = (vm_offset_t)page_metadata_get_freelist(page_meta);
 
-#if MACH_ASSERT
-       if (__improbable(!is_sane_zone_element(zone, old_head)))
+       if (__improbable(!is_sane_zone_element(zone, old_head))) {
                panic("zfree: invalid head pointer %p for freelist of zone %s\n",
-                     (void *) old_head, zone->zone_name);
-#endif
+                   (void *) old_head, zone->zone_name);
+       }
 
-       if (__improbable(!is_sane_zone_element(zone, element)))
+       if (__improbable(!is_sane_zone_element(zone, element))) {
                panic("zfree: freeing invalid pointer %p to zone %s\n",
-                     (void *) element, zone->zone_name);
+                   (void *) element, zone->zone_name);
+       }
 
+       if (__improbable(old_head == element)) {
+               panic("zfree: double free of %p to zone %s\n",
+                   (void *) element, zone->zone_name);
+       }
        /*
         * Always write a redundant next pointer
         * So that it is more difficult to forge, xor it with a random cookie
@@ -1217,9 +1334,9 @@ free_to_zone(zone_t      zone,
 
        *backup = old_head ^ (poison ? zp_poisoned_cookie : zp_nopoison_cookie);
 
-       /* 
-        * Insert this element at the head of the free list. We also xor the 
-        * primary pointer with the zp_nopoison_cookie to make sure a free 
+       /*
+        * Insert this element at the head of the free list. We also xor the
+        * primary pointer with the zp_nopoison_cookie to make sure a free
         * element does not provide the location of the next free element directly.
         */
        *primary             = old_head ^ zp_nopoison_cookie;
@@ -1256,8 +1373,8 @@ free_to_zone(zone_t      zone,
  */
 static inline vm_offset_t
 try_alloc_from_zone(zone_t zone,
-                       vm_tag_t tag __unused,
-                    boolean_t* check_poison)
+    vm_tag_t tag __unused,
+    boolean_t* check_poison)
 {
        vm_offset_t  element;
        struct zone_page_metadata *page_meta;
@@ -1265,11 +1382,11 @@ try_alloc_from_zone(zone_t zone,
        *check_poison = FALSE;
 
        /* if zone is empty, bail */
-       if (zone->allows_foreign && !queue_empty(&zone->pages.any_free_foreign))
+       if (zone->allows_foreign && !queue_empty(&zone->pages.any_free_foreign)) {
                page_meta = (struct zone_page_metadata *)queue_first(&zone->pages.any_free_foreign);
-       else if (!queue_empty(&zone->pages.intermediate))
+       } else if (!queue_empty(&zone->pages.intermediate)) {
                page_meta = (struct zone_page_metadata *)queue_first(&zone->pages.intermediate);
-       else if (!queue_empty(&zone->pages.all_free)) {
+       else if (!queue_empty(&zone->pages.all_free)) {
                page_meta = (struct zone_page_metadata *)queue_first(&zone->pages.all_free);
                assert(zone->count_all_free_pages >= page_meta->page_count);
                zone->count_all_free_pages -= page_meta->page_count;
@@ -1277,20 +1394,22 @@ try_alloc_from_zone(zone_t zone,
                return 0;
        }
        /* Check if page_meta passes is_sane_zone_element */
-       if (__improbable(!is_sane_zone_page_metadata(zone, (vm_offset_t)page_meta)))
+       if (__improbable(!is_sane_zone_page_metadata(zone, (vm_offset_t)page_meta))) {
                panic("zalloc: invalid metadata structure %p for freelist of zone %s\n",
-                       (void *) page_meta, zone->zone_name);
+                   (void *) page_meta, zone->zone_name);
+       }
        assert(PAGE_METADATA_GET_ZONE(page_meta) == zone);
        element = (vm_offset_t)page_metadata_get_freelist(page_meta);
 
-       if (__improbable(!is_sane_zone_ptr(zone, element, zone->elem_size)))
+       if (__improbable(!is_sane_zone_ptr(zone, element, zone->elem_size))) {
                panic("zfree: invalid head pointer %p for freelist of zone %s\n",
-                     (void *) element, zone->zone_name);
+                   (void *) element, zone->zone_name);
+       }
 
        vm_offset_t *primary = (vm_offset_t *) element;
        vm_offset_t *backup  = get_backup_ptr(zone->elem_size, primary);
 
-       /* 
+       /*
         * Since the primary next pointer is xor'ed with zp_nopoison_cookie
         * for obfuscation, retrieve the original value back
         */
@@ -1302,16 +1421,17 @@ try_alloc_from_zone(zone_t zone,
         * backup_ptr_mismatch_panic will determine what next_element
         * should have been, and print it appropriately
         */
-       if (__improbable(!is_sane_zone_element(zone, next_element)))
+       if (__improbable(!is_sane_zone_element(zone, next_element))) {
                backup_ptr_mismatch_panic(zone, element, next_element_primary, next_element_backup);
+       }
 
        /* Check the backup pointer for the regular cookie */
        if (__improbable(next_element != (next_element_backup ^ zp_nopoison_cookie))) {
-
                /* Check for the poisoned cookie instead */
-               if (__improbable(next_element != (next_element_backup ^ zp_poisoned_cookie)))
+               if (__improbable(next_element != (next_element_backup ^ zp_poisoned_cookie))) {
                        /* Neither cookie is valid, corruption has occurred */
                        backup_ptr_mismatch_panic(zone, element, next_element_primary, next_element_backup);
+               }
 
                /*
                 * Element was marked as poisoned, so check its integrity before using it.
@@ -1320,15 +1440,17 @@ try_alloc_from_zone(zone_t zone,
        }
 
        /* Make sure the page_meta is at the correct offset from the start of page */
-       if (__improbable(page_meta != get_zone_page_metadata((struct zone_free_element *)element, FALSE)))
+       if (__improbable(page_meta != get_zone_page_metadata((struct zone_free_element *)element, FALSE))) {
                panic("zalloc: Incorrect metadata %p found in zone %s page queue. Expected metadata: %p\n",
-                       page_meta, zone->zone_name, get_zone_page_metadata((struct zone_free_element *)element, FALSE));
+                   page_meta, zone->zone_name, get_zone_page_metadata((struct zone_free_element *)element, FALSE));
+       }
 
        /* Make sure next_element belongs to the same page as page_meta */
        if (next_element) {
-               if (__improbable(page_meta != get_zone_page_metadata((struct zone_free_element *)next_element, FALSE)))
+               if (__improbable(page_meta != get_zone_page_metadata((struct zone_free_element *)next_element, FALSE))) {
                        panic("zalloc: next element pointer %p for element %p points to invalid element for zone %s\n",
-                               (void *)next_element, (void *)element, zone->zone_name);
+                           (void *)next_element, (void *)element, zone->zone_name);
+               }
        }
 
        /* Remove this element from the free list */
@@ -1351,10 +1473,10 @@ try_alloc_from_zone(zone_t zone,
        zone->sum_count++;
 
 #if VM_MAX_TAG_ZONES
-    if (__improbable(zone->tags)) {
+       if (__improbable(zone->tags)) {
                // set the tag with b0 clear so the block remains inuse
                ZTAG(zone, element)[0] = (tag << 1);
-    }
+       }
 #endif /* VM_MAX_TAG_ZONES */
 
 
@@ -1372,26 +1494,26 @@ try_alloc_from_zone(zone_t zone,
 /*
  * Zone info options
  */
-#define ZINFO_SLOTS    MAX_ZONES               /* for now */
+#define ZINFO_SLOTS     MAX_ZONES               /* for now */
 
-zone_t         zone_find_largest(void);
+zone_t          zone_find_largest(void);
 
-/* 
- * Async allocation of zones 
- * This mechanism allows for bootstrapping an empty zone which is setup with 
+/*
+ * Async allocation of zones
+ * This mechanism allows for bootstrapping an empty zone which is setup with
  * non-blocking flags. The first call to zalloc_noblock() will kick off a thread_call
- * to zalloc_async. We perform a zalloc() (which may block) and then an immediate free. 
+ * to zalloc_async. We perform a zalloc() (which may block) and then an immediate free.
  * This will prime the zone for the next use.
  *
  * Currently the thread_callout function (zalloc_async) will loop through all zones
- * looking for any zone with async_pending set and do the work for it. 
- * 
+ * looking for any zone with async_pending set and do the work for it.
+ *
  * NOTE: If the calling thread for zalloc_noblock is lower priority than thread_call,
- * then zalloc_noblock to an empty zone may succeed. 
+ * then zalloc_noblock to an empty zone may succeed.
  */
-void           zalloc_async(
-                               thread_call_param_t     p0,  
-                               thread_call_param_t     p1);
+void            zalloc_async(
+       thread_call_param_t     p0,
+       thread_call_param_t     p1);
 
 static thread_call_data_t call_async_alloc;
 
@@ -1401,31 +1523,23 @@ static thread_call_data_t call_async_alloc;
 #define ZONE_ELEMENT_ALIGNMENT 32
 
 #define zone_wakeup(zone) thread_wakeup((event_t)(zone))
-#define zone_sleep(zone)                               \
+#define zone_sleep(zone)                                \
        (void) lck_mtx_sleep(&(zone)->lock, LCK_SLEEP_SPIN_ALWAYS, (event_t)(zone), THREAD_UNINT);
 
-/*
- *     The zone_locks_grp allows for collecting lock statistics.
- *     All locks are associated to this group in zinit.
- *     Look at tools/lockstat for debugging lock contention.
- */
-
-lck_grp_t      zone_locks_grp;
-lck_grp_attr_t zone_locks_grp_attr;
 
-#define lock_zone_init(zone)                           \
-MACRO_BEGIN                                            \
-       lck_attr_setdefault(&(zone)->lock_attr);                        \
-       lck_mtx_init_ext(&(zone)->lock, &(zone)->lock_ext,              \
-           &zone_locks_grp, &(zone)->lock_attr);                       \
+#define lock_zone_init(zone)                            \
+MACRO_BEGIN                                             \
+       lck_attr_setdefault(&(zone)->lock_attr);                        \
+       lck_mtx_init_ext(&(zone)->lock, &(zone)->lock_ext,              \
+           &zone_locks_grp, &(zone)->lock_attr);                       \
 MACRO_END
 
-#define lock_try_zone(zone)    lck_mtx_try_lock_spin(&zone->lock)
+#define lock_try_zone(zone)     lck_mtx_try_lock_spin(&zone->lock)
 
 /*
  *     Exclude more than one concurrent garbage collection
  */
-decl_lck_mtx_data(, zone_gc_lock)
+decl_lck_mtx_data(, zone_gc_lock);
 
 lck_attr_t      zone_gc_lck_attr;
 lck_grp_t       zone_gc_lck_grp;
@@ -1438,9 +1552,12 @@ boolean_t panic_include_zprint = FALSE;
 mach_memory_info_t *panic_kext_memory_info = NULL;
 vm_size_t panic_kext_memory_size = 0;
 
-#define ZALLOC_DEBUG_ZONEGC            0x00000001
-#define ZALLOC_DEBUG_ZCRAM             0x00000002
-uint32_t zalloc_debug = 0;
+#define ZALLOC_DEBUG_ZONEGC             0x00000001
+#define ZALLOC_DEBUG_ZCRAM              0x00000002
+
+#if DEBUG || DEVELOPMENT
+static uint32_t zalloc_debug = 0;
+#endif
 
 /*
  * Zone leak debugging code
@@ -1451,7 +1568,7 @@ uint32_t zalloc_debug = 0;
  * off by default.
  *
  * Enable the logging via the boot-args. Add the parameter "zlog=<zone>" to boot-args where <zone>
- * is the name of the zone you wish to log.  
+ * is the name of the zone you wish to log.
  *
  * This code only tracks one zone, so you need to identify which one is leaking first.
  * Generally, you'll know you have a leak when you get a "zalloc retry failed 3" panic from the zone
@@ -1473,17 +1590,17 @@ uint32_t zalloc_debug = 0;
  */
 
 static boolean_t log_records_init = FALSE;
-static int log_records;        /* size of the log, expressed in number of records */
+static int log_records; /* size of the log, expressed in number of records */
 
-#define MAX_NUM_ZONES_ALLOWED_LOGGING  10 /* Maximum 10 zones can be logged at once */
+#define MAX_NUM_ZONES_ALLOWED_LOGGING   10 /* Maximum 10 zones can be logged at once */
 
 static int  max_num_zones_to_log = MAX_NUM_ZONES_ALLOWED_LOGGING;
 static int  num_zones_logged = 0;
 
-static char zone_name_to_log[MAX_ZONE_NAME] = "";      /* the zone name we're logging, if any */
+static char zone_name_to_log[MAX_ZONE_NAME] = "";       /* the zone name we're logging, if any */
 
 /* Log allocations and frees to help debug a zone element corruption */
-boolean_t       corruption_debug_flag    = FALSE;    /* enabled by "-zc" boot-arg */
+boolean_t       corruption_debug_flag    = DEBUG;    /* enabled by "-zc" boot-arg */
 /* Making pointer scanning leaks detection possible for all zones */
 
 #if DEBUG || DEVELOPMENT
@@ -1492,17 +1609,17 @@ boolean_t       leak_scan_debug_flag     = FALSE;    /* enabled by "-zl" boot-ar
 
 
 /*
- * The number of records in the log is configurable via the zrecs parameter in boot-args.  Set this to 
+ * The number of records in the log is configurable via the zrecs parameter in boot-args.  Set this to
  * the number of records you want in the log.  For example, "zrecs=10" sets it to 10 records. Since this
  * is the number of stacks suspected of leaking, we don't need many records.
  */
 
-#if    defined(__LP64__)
-#define ZRECORDS_MAX           2560            /* Max records allowed in the log */
+#if     defined(__LP64__)
+#define ZRECORDS_MAX            2560            /* Max records allowed in the log */
 #else
-#define ZRECORDS_MAX           1536            /* Max records allowed in the log */
+#define ZRECORDS_MAX            1536            /* Max records allowed in the log */
 #endif
-#define ZRECORDS_DEFAULT       1024            /* default records in log if zrecs is not specificed in boot-args */
+#define ZRECORDS_DEFAULT        1024            /* default records in log if zrecs is not specificed in boot-args */
 
 /*
  * Each record in the log contains a pointer to the zone element it refers to,
@@ -1513,13 +1630,6 @@ boolean_t       leak_scan_debug_flag     = FALSE;    /* enabled by "-zl" boot-ar
  */
 
 
-/*
- * Opcodes for the btlog operation field:
- */
-
-#define ZOP_ALLOC      1
-#define ZOP_FREE       0
-
 /*
  * Decide if we want to log this zone by doing a string compare between a zone name and the name
  * of the zone to log. Return true if the strings are equal, false otherwise.  Because it's not
@@ -1530,7 +1640,7 @@ boolean_t       leak_scan_debug_flag     = FALSE;    /* enabled by "-zl" boot-ar
 int
 track_this_zone(const char *zonename, const char *logname)
 {
-       int len;
+       unsigned int len;
        const char *zc = zonename;
        const char *lc = logname;
 
@@ -1539,22 +1649,23 @@ track_this_zone(const char *zonename, const char *logname)
         */
 
        for (len = 1; len <= MAX_ZONE_NAME; zc++, lc++, len++) {
-
                /*
                 * If the current characters don't match, check for a space in
                 * in the zone name and a corresponding period in the log name.
                 * If that's not there, then the strings don't match.
                 */
 
-               if (*zc != *lc && !(*zc == ' ' && *lc == '.')) 
+               if (*zc != *lc && !(*zc == ' ' && *lc == '.')) {
                        break;
+               }
 
                /*
                 * The strings are equal so far.  If we're at the end, then it's a match.
                 */
 
-               if (*zc == '\0')
+               if (*zc == '\0') {
                        return TRUE;
+               }
        }
 
        return FALSE;
@@ -1566,7 +1677,7 @@ track_this_zone(const char *zonename, const char *logname)
  * the buffer for the records has been allocated.
  */
 
-#define DO_LOGGING(z)          (z->zone_logging == TRUE && z->zlog_btlog)
+#define DO_LOGGING(z)           (z->zone_logging == TRUE && z->zlog_btlog)
 
 extern boolean_t kmem_alloc_ready;
 
@@ -1574,13 +1685,13 @@ extern boolean_t kmem_alloc_ready;
 #pragma mark -
 #pragma mark Zone Leak Detection
 
-/* 
+/*
  * The zone leak detector, abbreviated 'zleak', keeps track of a subset of the currently outstanding
  * allocations made by the zone allocator.  Every zleak_sample_factor allocations in each zone, we capture a
- * backtrace.  Every free, we examine the table and determine if the allocation was being tracked, 
+ * backtrace.  Every free, we examine the table and determine if the allocation was being tracked,
  * and stop tracking it if it was being tracked.
  *
- * We track the allocations in the zallocations hash table, which stores the address that was returned from 
+ * We track the allocations in the zallocations hash table, which stores the address that was returned from
  * the zone allocator.  Each stored entry in the zallocations table points to an entry in the ztraces table, which
  * stores the backtrace associated with that allocation.  This provides uniquing for the relatively large
  * backtraces - we don't store them more than once.
@@ -1588,20 +1699,20 @@ extern boolean_t kmem_alloc_ready;
  * Data collection begins when the zone map is 50% full, and only occurs for zones that are taking up
  * a large amount of virtual space.
  */
-#define ZLEAK_STATE_ENABLED            0x01    /* Zone leak monitoring should be turned on if zone_map fills up. */
-#define ZLEAK_STATE_ACTIVE             0x02    /* We are actively collecting traces. */
-#define ZLEAK_STATE_ACTIVATING                 0x04    /* Some thread is doing setup; others should move along. */
-#define ZLEAK_STATE_FAILED             0x08    /* Attempt to allocate tables failed.  We will not try again. */
-uint32_t       zleak_state = 0;                /* State of collection, as above */
+#define ZLEAK_STATE_ENABLED             0x01    /* Zone leak monitoring should be turned on if zone_map fills up. */
+#define ZLEAK_STATE_ACTIVE              0x02    /* We are actively collecting traces. */
+#define ZLEAK_STATE_ACTIVATING          0x04    /* Some thread is doing setup; others should move along. */
+#define ZLEAK_STATE_FAILED              0x08    /* Attempt to allocate tables failed.  We will not try again. */
+uint32_t        zleak_state = 0;                /* State of collection, as above */
 
-boolean_t      panic_include_ztrace    = FALSE;        /* Enable zleak logging on panic */
-vm_size_t      zleak_global_tracking_threshold;        /* Size of zone map at which to start collecting data */
-vm_size_t      zleak_per_zone_tracking_threshold;      /* Size a zone will have before we will collect data on it */
-unsigned int   zleak_sample_factor     = 1000;         /* Allocations per sample attempt */
+boolean_t       panic_include_ztrace    = FALSE;        /* Enable zleak logging on panic */
+vm_size_t       zleak_global_tracking_threshold;        /* Size of zone map at which to start collecting data */
+vm_size_t       zleak_per_zone_tracking_threshold;      /* Size a zone will have before we will collect data on it */
+unsigned int    zleak_sample_factor     = 1000;         /* Allocations per sample attempt */
 
 /*
  * Counters for allocation statistics.
- */ 
+ */
 
 /* Times two active records want to occupy the same spot */
 unsigned int z_alloc_collisions = 0;
@@ -1612,11 +1723,11 @@ unsigned int z_alloc_overwrites = 0;
 unsigned int z_trace_overwrites = 0;
 
 /* Times a new alloc or trace is put into the hash table */
-unsigned int z_alloc_recorded  = 0;
-unsigned int z_trace_recorded  = 0;
+unsigned int z_alloc_recorded   = 0;
+unsigned int z_trace_recorded   = 0;
 
 /* Times zleak_log returned false due to not being able to acquire the lock */
-unsigned int z_total_conflicts = 0;
+unsigned int z_total_conflicts  = 0;
 
 
 #pragma mark struct zallocation
@@ -1625,11 +1736,11 @@ unsigned int z_total_conflicts  = 0;
  * An allocation bucket is in use if its element is not NULL
  */
 struct zallocation {
-       uintptr_t               za_element;             /* the element that was zalloc'ed or zfree'ed, NULL if bucket unused */
-       vm_size_t               za_size;                        /* how much memory did this allocation take up? */
-       uint32_t                za_trace_index; /* index into ztraces for backtrace associated with allocation */
+       uintptr_t               za_element;             /* the element that was zalloc'ed or zfree'ed, NULL if bucket unused */
+       vm_size_t               za_size;                        /* how much memory did this allocation take up? */
+       uint32_t                za_trace_index; /* index into ztraces for backtrace associated with allocation */
        /* TODO: #if this out */
-       uint32_t                za_hit_count;           /* for determining effectiveness of hash function */
+       uint32_t                za_hit_count;           /* for determining effectiveness of hash function */
 };
 
 /* Size must be a power of two for the zhash to be able to just mask off bits instead of mod */
@@ -1639,29 +1750,29 @@ uint32_t zleak_trace_buckets = CONFIG_ZLEAK_TRACE_MAP_NUM;
 vm_size_t zleak_max_zonemap_size;
 
 /* Hashmaps of allocations and their corresponding traces */
-static struct zallocation*     zallocations;
-static struct ztrace*          ztraces;
+static struct zallocation*      zallocations;
+static struct ztrace*           ztraces;
 
 /* not static so that panic can see this, see kern/debug.c */
-struct ztrace*                         top_ztrace;
+struct ztrace*                          top_ztrace;
 
 /* Lock to protect zallocations, ztraces, and top_ztrace from concurrent modification. */
-static lck_spin_t                      zleak_lock;
-static lck_attr_t                      zleak_lock_attr;
-static lck_grp_t                       zleak_lock_grp;
-static lck_grp_attr_t                  zleak_lock_grp_attr;
+static lck_spin_t                       zleak_lock;
+static lck_attr_t                       zleak_lock_attr;
+static lck_grp_t                        zleak_lock_grp;
+static lck_grp_attr_t                   zleak_lock_grp_attr;
 
 /*
  * Initializes the zone leak monitor.  Called from zone_init()
  */
-static void 
-zleak_init(vm_size_t max_zonemap_size) 
+static void
+zleak_init(vm_size_t max_zonemap_size)
 {
-       char                    scratch_buf[16];
-       boolean_t               zleak_enable_flag = FALSE;
+       char                    scratch_buf[16];
+       boolean_t               zleak_enable_flag = FALSE;
 
        zleak_max_zonemap_size = max_zonemap_size;
-       zleak_global_tracking_threshold = max_zonemap_size / 2; 
+       zleak_global_tracking_threshold = max_zonemap_size / 2;
        zleak_per_zone_tracking_threshold = zleak_global_tracking_threshold / 8;
 
 #if CONFIG_EMBEDDED
@@ -1682,7 +1793,7 @@ zleak_init(vm_size_t max_zonemap_size)
                printf("zone leak detection enabled\n");
        }
 #endif /* CONFIG_EMBEDDED */
-       
+
        /* zfactor=XXXX (override how often to sample the zone allocator) */
        if (PE_parse_boot_argn("zfactor", &zleak_sample_factor, sizeof(zleak_sample_factor))) {
                printf("Zone leak factor override: %u\n", zleak_sample_factor);
@@ -1692,26 +1803,26 @@ zleak_init(vm_size_t max_zonemap_size)
        if (PE_parse_boot_argn("zleak-allocs", &zleak_alloc_buckets, sizeof(zleak_alloc_buckets))) {
                printf("Zone leak alloc buckets override: %u\n", zleak_alloc_buckets);
                /* uses 'is power of 2' trick: (0x01000 & 0x00FFF == 0) */
-               if (zleak_alloc_buckets == 0 || (zleak_alloc_buckets & (zleak_alloc_buckets-1))) {
+               if (zleak_alloc_buckets == 0 || (zleak_alloc_buckets & (zleak_alloc_buckets - 1))) {
                        printf("Override isn't a power of two, bad things might happen!\n");
                }
        }
-       
+
        /* zleak-traces=XXXX (override number of buckets in ztraces) */
        if (PE_parse_boot_argn("zleak-traces", &zleak_trace_buckets, sizeof(zleak_trace_buckets))) {
                printf("Zone leak trace buckets override: %u\n", zleak_trace_buckets);
                /* uses 'is power of 2' trick: (0x01000 & 0x00FFF == 0) */
-               if (zleak_trace_buckets == 0 || (zleak_trace_buckets & (zleak_trace_buckets-1))) {
+               if (zleak_trace_buckets == 0 || (zleak_trace_buckets & (zleak_trace_buckets - 1))) {
                        printf("Override isn't a power of two, bad things might happen!\n");
                }
        }
-       
+
        /* allocate the zleak_lock */
        lck_grp_attr_setdefault(&zleak_lock_grp_attr);
        lck_grp_init(&zleak_lock_grp, "zleak_lock", &zleak_lock_grp_attr);
        lck_attr_setdefault(&zleak_lock_attr);
        lck_spin_init(&zleak_lock, &zleak_lock_grp, &zleak_lock_attr);
-       
+
        if (zleak_enable_flag) {
                zleak_state = ZLEAK_STATE_ENABLED;
        }
@@ -1726,11 +1837,13 @@ zleak_init(vm_size_t max_zonemap_size)
 int
 get_zleak_state(void)
 {
-       if (zleak_state & ZLEAK_STATE_FAILED)
-               return (-1);
-       if (zleak_state & ZLEAK_STATE_ACTIVE)
-               return (1);
-       return (0);
+       if (zleak_state & ZLEAK_STATE_FAILED) {
+               return -1;
+       }
+       if (zleak_state & ZLEAK_STATE_ACTIVE) {
+               return 1;
+       }
+       return 0;
 }
 
 #endif
@@ -1779,7 +1892,7 @@ zleak_activate(void)
        ztraces = traces_ptr;
 
        /*
-        * Initialize the top_ztrace to the first entry in ztraces, 
+        * Initialize the top_ztrace to the first entry in ztraces,
         * so we don't have to check for null in zleak_log
         */
        top_ztrace = &ztraces[0];
@@ -1793,10 +1906,10 @@ zleak_activate(void)
        zleak_state |= ZLEAK_STATE_ACTIVE;
        zleak_state &= ~ZLEAK_STATE_ACTIVATING;
        lck_spin_unlock(&zleak_lock);
-       
+
        return 0;
 
-fail:  
+fail:
        /*
         * If we fail to allocate memory, don't further tax
         * the system by trying again.
@@ -1818,15 +1931,15 @@ fail:
 }
 
 /*
- * TODO: What about allocations that never get deallocated, 
+ * TODO: What about allocations that never get deallocated,
  * especially ones with unique backtraces? Should we wait to record
- * until after boot has completed?  
+ * until after boot has completed?
  * (How many persistent zallocs are there?)
  */
 
 /*
- * This function records the allocation in the allocations table, 
- * and stores the associated backtrace in the traces table 
+ * This function records the allocation in the allocations table,
+ * and stores the associated backtrace in the traces table
  * (or just increments the refcount if the trace is already recorded)
  * If the allocation slot is in use, the old allocation is replaced with the new allocation, and
  * the associated trace's refcount is decremented.
@@ -1836,47 +1949,47 @@ fail:
  */
 static boolean_t
 zleak_log(uintptr_t* bt,
-                 uintptr_t addr,
-                 uint32_t depth,
-                 vm_size_t allocation_size) 
+    uintptr_t addr,
+    uint32_t depth,
+    vm_size_t allocation_size)
 {
        /* Quit if there's someone else modifying the hash tables */
        if (!lck_spin_try_lock(&zleak_lock)) {
                z_total_conflicts++;
                return FALSE;
        }
-       
-       struct zallocation* allocation  = &zallocations[hashaddr(addr, zleak_alloc_buckets)];
-       
+
+       struct zallocation* allocation  = &zallocations[hashaddr(addr, zleak_alloc_buckets)];
+
        uint32_t trace_index = hashbacktrace(bt, depth, zleak_trace_buckets);
        struct ztrace* trace = &ztraces[trace_index];
-       
+
        allocation->za_hit_count++;
        trace->zt_hit_count++;
-       
-       /* 
+
+       /*
         * If the allocation bucket we want to be in is occupied, and if the occupier
-        * has the same trace as us, just bail.  
+        * has the same trace as us, just bail.
         */
        if (allocation->za_element != (uintptr_t) 0 && trace_index == allocation->za_trace_index) {
                z_alloc_collisions++;
-               
+
                lck_spin_unlock(&zleak_lock);
                return TRUE;
        }
-       
+
        /* STEP 1: Store the backtrace in the traces array. */
        /* A size of zero indicates that the trace bucket is free. */
-       
-       if (trace->zt_size > 0 && bcmp(trace->zt_stack, bt, (depth * sizeof(uintptr_t))) != 0 ) {
-               /* 
+
+       if (trace->zt_size > 0 && bcmp(trace->zt_stack, bt, (depth * sizeof(uintptr_t))) != 0) {
+               /*
                 * Different unique trace with same hash!
                 * Just bail - if we're trying to record the leaker, hopefully the other trace will be deallocated
                 * and get out of the way for later chances
                 */
                trace->zt_collisions++;
                z_trace_collisions++;
-               
+
                lck_spin_unlock(&zleak_lock);
                return TRUE;
        } else if (trace->zt_size > 0) {
@@ -1884,28 +1997,29 @@ zleak_log(uintptr_t* bt,
                trace->zt_size += allocation_size;
        } else {
                /* Found an unused trace bucket, record the trace here! */
-               if (trace->zt_depth != 0) /* if this slot was previously used but not currently in use */
+               if (trace->zt_depth != 0) /* if this slot was previously used but not currently in use */
                        z_trace_overwrites++;
-               
+               }
+
                z_trace_recorded++;
-               trace->zt_size                  = allocation_size;
-               memcpy(trace->zt_stack, bt, (depth * sizeof(uintptr_t)) );
-               
-               trace->zt_depth         = depth;
-               trace->zt_collisions    = 0;
+               trace->zt_size                  = allocation_size;
+               memcpy(trace->zt_stack, bt, (depth * sizeof(uintptr_t)));
+
+               trace->zt_depth         = depth;
+               trace->zt_collisions    = 0;
        }
-       
+
        /* STEP 2: Store the allocation record in the allocations array. */
-       
+
        if (allocation->za_element != (uintptr_t) 0) {
-               /* 
+               /*
                 * Straight up replace any allocation record that was there.  We don't want to do the work
-                * to preserve the allocation entries that were there, because we only record a subset of the 
+                * to preserve the allocation entries that were there, because we only record a subset of the
                 * allocations anyways.
                 */
-               
+
                z_alloc_collisions++;
-               
+
                struct ztrace* associated_trace = &ztraces[allocation->za_trace_index];
                /* Knock off old allocation's size, not the new allocation */
                associated_trace->zt_size -= allocation->za_size;
@@ -1914,15 +2028,16 @@ zleak_log(uintptr_t* bt,
                z_alloc_overwrites++;
        }
 
-       allocation->za_element          = addr;
-       allocation->za_trace_index      = trace_index;
-       allocation->za_size             = allocation_size;
-       
+       allocation->za_element          = addr;
+       allocation->za_trace_index      = trace_index;
+       allocation->za_size             = allocation_size;
+
        z_alloc_recorded++;
-       
-       if (top_ztrace->zt_size < trace->zt_size)
+
+       if (top_ztrace->zt_size < trace->zt_size) {
                top_ztrace = trace;
-       
+       }
+
        lck_spin_unlock(&zleak_lock);
        return TRUE;
 }
@@ -1933,37 +2048,38 @@ zleak_log(uintptr_t* bt,
  */
 static void
 zleak_free(uintptr_t addr,
-                  vm_size_t allocation_size) 
+    vm_size_t allocation_size)
 {
-       if (addr == (uintptr_t) 0)
+       if (addr == (uintptr_t) 0) {
                return;
-       
+       }
+
        struct zallocation* allocation = &zallocations[hashaddr(addr, zleak_alloc_buckets)];
-       
+
        /* Double-checked locking: check to find out if we're interested, lock, check to make
         * sure it hasn't changed, then modify it, and release the lock.
         */
-       
+
        if (allocation->za_element == addr && allocation->za_trace_index < zleak_trace_buckets) {
                /* if the allocation was the one, grab the lock, check again, then delete it */
                lck_spin_lock(&zleak_lock);
-               
+
                if (allocation->za_element == addr && allocation->za_trace_index < zleak_trace_buckets) {
                        struct ztrace *trace;
 
                        /* allocation_size had better match what was passed into zleak_log - otherwise someone is freeing into the wrong zone! */
                        if (allocation->za_size != allocation_size) {
-                               panic("Freeing as size %lu memory that was allocated with size %lu\n", 
-                                               (uintptr_t)allocation_size, (uintptr_t)allocation->za_size);
+                               panic("Freeing as size %lu memory that was allocated with size %lu\n",
+                                   (uintptr_t)allocation_size, (uintptr_t)allocation->za_size);
                        }
-                       
+
                        trace = &ztraces[allocation->za_trace_index];
-                       
+
                        /* size of 0 indicates trace bucket is unused */
                        if (trace->zt_size > 0) {
                                trace->zt_size -= allocation_size;
                        }
-                       
+
                        /* A NULL element means the allocation bucket is unused */
                        allocation->za_element = 0;
                }
@@ -1984,16 +2100,16 @@ hash_mix(uintptr_t x)
 #ifndef __LP64__
        x += ~(x << 15);
        x ^=  (x >> 10);
-       x +=  (x << 3 );
-       x ^=  (x >> 6 );
+       x +=  (x << 3);
+       x ^=  (x >> 6);
        x += ~(x << 11);
        x ^=  (x >> 16);
 #else
        x += ~(x << 32);
        x ^=  (x >> 22);
        x += ~(x << 13);
-       x ^=  (x >> 8 );
-       x +=  (x << 3 );
+       x ^=  (x >> 8);
+       x +=  (x << 3);
        x ^=  (x >> 15);
        x += ~(x << 27);
        x ^=  (x >> 31);
@@ -2004,7 +2120,6 @@ hash_mix(uintptr_t x)
 uint32_t
 hashbacktrace(uintptr_t* bt, uint32_t depth, uint32_t max_size)
 {
-
        uintptr_t hash = 0;
        uintptr_t mask = max_size - 1;
 
@@ -2039,7 +2154,7 @@ hashaddr(uintptr_t pt, uint32_t max_size)
 /* End of all leak-detection code */
 #pragma mark -
 
-#define ZONE_MAX_ALLOC_SIZE    (32 * 1024) 
+#define ZONE_MAX_ALLOC_SIZE     (32 * 1024)
 #define ZONE_ALLOC_FRAG_PERCENT(alloc_size, ele_size) (((alloc_size % ele_size) * 100) / alloc_size)
 
 /* Used to manage copying in of new zone names */
@@ -2053,45 +2168,141 @@ compute_element_size(vm_size_t requested_size)
 
        /* Zone elements must fit both a next pointer and a backup pointer */
        vm_size_t  minimum_element_size = sizeof(vm_offset_t) * 2;
-       if (element_size < minimum_element_size)
+       if (element_size < minimum_element_size) {
                element_size = minimum_element_size;
+       }
 
        /*
         *  Round element size to a multiple of sizeof(pointer)
         *  This also enforces that allocations will be aligned on pointer boundaries
         */
-       element_size = ((element_size-1) + sizeof(vm_offset_t)) -
-              ((element_size-1) % sizeof(vm_offset_t));
+       element_size = ((element_size - 1) + sizeof(vm_offset_t)) -
+           ((element_size - 1) % sizeof(vm_offset_t));
 
        return element_size;
 }
 
+#if KASAN_ZALLOC
+
 /*
- *     zinit initializes a new zone.  The zone data structures themselves
- *     are stored in a zone, which is initially a static structure that
- *     is initialized by zone_init.
+ * Called from zinit().
+ *
+ * Fixes up the zone's element size to incorporate the redzones.
  */
-
-zone_t
-zinit(
-       vm_size_t       size,           /* the size of an element */
-       vm_size_t       max,            /* maximum memory to use */
-       vm_size_t       alloc,          /* allocation size */
-       const char      *name)          /* a name for the zone */
+static void
+kasan_update_element_size_for_redzone(
+       zone_t          zone,           /* the zone that needs to be updated */
+       vm_size_t       *size,          /* requested zone element size */
+       vm_size_t       *max,           /* maximum memory to use */
+       const char      *name)          /* zone name */
 {
-       zone_t                  z;
-
-       size = compute_element_size(size);
+       /* Expand the zone allocation size to include the redzones. For page-multiple
+        * zones add a full guard page because they likely require alignment. kalloc
+        * and fakestack handles its own KASan state, so ignore those zones. */
+       /* XXX: remove this when zinit_with_options() is a thing */
+       const char *kalloc_name = "kalloc.";
+       const char *fakestack_name = "fakestack.";
+       if (strncmp(name, kalloc_name, strlen(kalloc_name)) == 0) {
+               zone->kasan_redzone = 0;
+       } else if (strncmp(name, fakestack_name, strlen(fakestack_name)) == 0) {
+               zone->kasan_redzone = 0;
+       } else {
+               if ((*size % PAGE_SIZE) != 0) {
+                       zone->kasan_redzone = KASAN_GUARD_SIZE;
+               } else {
+                       zone->kasan_redzone = PAGE_SIZE;
+               }
+               *max = (*max / *size) * (*size + zone->kasan_redzone * 2);
+               *size += zone->kasan_redzone * 2;
+       }
+}
+
+/*
+ * Called from zalloc_internal() to fix up the address of the newly
+ * allocated element.
+ *
+ * Returns the element address skipping over the redzone on the left.
+ */
+static vm_offset_t
+kasan_fixup_allocated_element_address(
+       zone_t                  zone,   /* the zone the element belongs to */
+       vm_offset_t             addr)   /* address of the element, including the redzone */
+{
+       /* Fixup the return address to skip the redzone */
+       if (zone->kasan_redzone) {
+               addr = kasan_alloc(addr, zone->elem_size,
+                   zone->elem_size - 2 * zone->kasan_redzone, zone->kasan_redzone);
+       }
+       return addr;
+}
+
+/*
+ * Called from zfree() to add the element being freed to the KASan quarantine.
+ *
+ * Returns true if the newly-freed element made it into the quarantine without
+ * displacing another, false otherwise. In the latter case, addrp points to the
+ * address of the displaced element, which will be freed by the zone.
+ */
+static bool
+kasan_quarantine_freed_element(
+       zone_t          *zonep,         /* the zone the element is being freed to */
+       void            **addrp)        /* address of the element being freed */
+{
+       zone_t zone = *zonep;
+       void *addr = *addrp;
+
+       /*
+        * Resize back to the real allocation size and hand off to the KASan
+        * quarantine. `addr` may then point to a different allocation, if the
+        * current element replaced another in the quarantine. The zone then
+        * takes ownership of the swapped out free element.
+        */
+       vm_size_t usersz = zone->elem_size - 2 * zone->kasan_redzone;
+       vm_size_t sz = usersz;
+
+       if (addr && zone->kasan_redzone) {
+               kasan_check_free((vm_address_t)addr, usersz, KASAN_HEAP_ZALLOC);
+               addr = (void *)kasan_dealloc((vm_address_t)addr, &sz);
+               assert(sz == zone->elem_size);
+       }
+       if (addr && zone->kasan_quarantine) {
+               kasan_free(&addr, &sz, KASAN_HEAP_ZALLOC, zonep, usersz, true);
+               if (!addr) {
+                       return TRUE;
+               }
+       }
+       *addrp = addr;
+       return FALSE;
+}
+
+#endif /* KASAN_ZALLOC */
 
-       simple_lock(&all_zones_lock);
+/*
+ *     zinit initializes a new zone.  The zone data structures themselves
+ *     are stored in a zone, which is initially a static structure that
+ *     is initialized by zone_init.
+ */
+
+zone_t
+zinit(
+       vm_size_t       size,           /* the size of an element */
+       vm_size_t       max,            /* maximum memory to use */
+       vm_size_t       alloc,          /* allocation size */
+       const char      *name)          /* a name for the zone */
+{
+       zone_t                  z;
+
+       size = compute_element_size(size);
+
+       simple_lock(&all_zones_lock, &zone_locks_grp);
 
        assert(num_zones < MAX_ZONES);
        assert(num_zones_in_use <= num_zones);
 
        /* If possible, find a previously zdestroy'ed zone in the zone_array that we can reuse instead of initializing a new zone. */
        for (int index = bitmap_first(zone_empty_bitmap, MAX_ZONES);
-                       index >= 0 && index < (int)num_zones;
-                       index = bitmap_next(zone_empty_bitmap, index)) {
+           index >= 0 && index < (int)num_zones;
+           index = bitmap_next(zone_empty_bitmap, index)) {
                z = &(zone_array[index]);
 
                /*
@@ -2108,10 +2319,11 @@ zinit(
                                bitmap_clear(zone_empty_bitmap, index);
                                num_zones_in_use++;
                                z->zone_valid = TRUE;
+                               z->zone_destruction = FALSE;
 
                                /* All other state is already set up since the zone was previously in use. Return early. */
                                simple_unlock(&all_zones_lock);
-                               return (z);
+                               return z;
                        }
                }
        }
@@ -2136,25 +2348,7 @@ zinit(
        simple_unlock(&all_zones_lock);
 
 #if KASAN_ZALLOC
-       /* Expand the zone allocation size to include the redzones. For page-multiple
-        * zones add a full guard page because they likely require alignment. kalloc
-        * and fakestack handles its own KASan state, so ignore those zones. */
-       /* XXX: remove this when zinit_with_options() is a thing */
-       const char *kalloc_name = "kalloc.";
-       const char *fakestack_name = "fakestack.";
-       if (strncmp(name, kalloc_name, strlen(kalloc_name)) == 0) {
-               z->kasan_redzone = 0;
-       } else if (strncmp(name, fakestack_name, strlen(fakestack_name)) == 0) {
-               z->kasan_redzone = 0;
-       } else {
-               if ((size % PAGE_SIZE) != 0) {
-                       z->kasan_redzone = KASAN_GUARD_SIZE;
-               } else {
-                       z->kasan_redzone = PAGE_SIZE;
-               }
-               max = (max / size) * (size + z->kasan_redzone * 2);
-               size += z->kasan_redzone * 2;
-       }
+       kasan_update_element_size_for_redzone(z, &size, &max, name);
 #endif
 
        max = round_page(max);
@@ -2174,8 +2368,9 @@ zinit(
        }
 
        alloc = best_alloc;
-       if (max && (max < alloc))
+       if (max && (max < alloc)) {
                max = alloc;
+       }
 
        z->free_elements = NULL;
        queue_init(&z->pages.any_free_foreign);
@@ -2211,6 +2406,9 @@ zinit(
        z->zp_count = 0;
        z->kasan_quarantine = TRUE;
        z->zone_valid = TRUE;
+       z->zone_destruction = FALSE;
+       z->cpu_cache_enabled = FALSE;
+       z->clear_memory = FALSE;
 
 #if CONFIG_ZLEAKS
        z->zleak_capture = 0;
@@ -2225,12 +2423,12 @@ zinit(
         * kexts can be loaded (unloaded). So we should be fine with just a pointer in this case.
         */
        if (kmem_alloc_ready) {
-               size_t len = MIN(strlen(name)+1, MACH_ZONE_NAME_MAX_LEN);
+               size_t len = MIN(strlen(name) + 1, MACH_ZONE_NAME_MAX_LEN);
 
                if (zone_names_start == 0 || ((zone_names_next - zone_names_start) + len) > PAGE_SIZE) {
                        printf("zalloc: allocating memory for zone names buffer\n");
                        kern_return_t retval = kmem_alloc_kobject(kernel_map, &zone_names_start,
-                                       PAGE_SIZE, VM_KERN_MEMORY_OSFMK);
+                           PAGE_SIZE, VM_KERN_MEMORY_OSFMK);
                        if (retval != KERN_SUCCESS) {
                                panic("zalloc: zone_names memory allocation failed");
                        }
@@ -2257,13 +2455,11 @@ zinit(
         */
 
        if (num_zones_logged < max_num_zones_to_log) {
-
-               int             i = 1; /* zlog0 isn't allowed. */
-               boolean_t       zone_logging_enabled = FALSE;
-               char            zlog_name[MAX_ZONE_NAME] = ""; /* Temp. buffer to create the strings zlog1, zlog2 etc... */
+               int             i = 1; /* zlog0 isn't allowed. */
+               boolean_t       zone_logging_enabled = FALSE;
+               char            zlog_name[MAX_ZONE_NAME] = ""; /* Temp. buffer to create the strings zlog1, zlog2 etc... */
 
                while (i <= max_num_zones_to_log) {
-
                        snprintf(zlog_name, MAX_ZONE_NAME, "zlog%d", i);
 
                        if (PE_parse_boot_argn(zlog_name, zone_name_to_log, sizeof(zone_name_to_log)) == TRUE) {
@@ -2280,7 +2476,7 @@ zinit(
                }
 
                if (zone_logging_enabled == FALSE) {
-                       /* 
+                       /*
                         * Backwards compat. with the old boot-arg used to specify single zone logging i.e. zlog
                         * Needs to happen after the newer zlogn checks because the prefix will match all the zlogn
                         * boot-args.
@@ -2297,7 +2493,7 @@ zinit(
                }
 
                if (log_records_init == FALSE && zone_logging_enabled == TRUE) {
-                   if (PE_parse_boot_argn("zrecs", &log_records, sizeof(log_records)) == TRUE) {
+                       if (PE_parse_boot_argn("zrecs", &log_records, sizeof(log_records)) == TRUE) {
                                /*
                                 * Don't allow more than ZRECORDS_MAX records even if the user asked for more.
                                 * This prevents accidentally hogging too much kernel memory and making the system
@@ -2321,16 +2517,14 @@ zinit(
                 * right now.
                 */
                if (kmem_alloc_ready) {
-
                        zone_t curr_zone = NULL;
                        unsigned int max_zones = 0, zone_idx = 0;
 
-                       simple_lock(&all_zones_lock);
+                       simple_lock(&all_zones_lock, &zone_locks_grp);
                        max_zones = num_zones;
                        simple_unlock(&all_zones_lock);
 
                        for (zone_idx = 0; zone_idx < max_zones; zone_idx++) {
-
                                curr_zone = &(zone_array[zone_idx]);
 
                                if (!curr_zone->zone_valid) {
@@ -2345,36 +2539,40 @@ zinit(
                                 * We don't expect these zones to be needed at this early a time in boot and so take this chance.
                                 */
                                if (curr_zone->zone_logging && curr_zone->zlog_btlog == NULL) {
-
                                        curr_zone->zlog_btlog = btlog_create(log_records, MAX_ZTRACE_DEPTH, (corruption_debug_flag == FALSE) /* caller_will_remove_entries_for_element? */);
 
                                        if (curr_zone->zlog_btlog) {
-
                                                printf("zone: logging started for zone %s\n", curr_zone->zone_name);
                                        } else {
                                                printf("zone: couldn't allocate memory for zrecords, turning off zleak logging\n");
                                                curr_zone->zone_logging = FALSE;
                                        }
                                }
-
                        }
                }
        }
 
-#if    CONFIG_GZALLOC  
+#if     CONFIG_GZALLOC
        gzalloc_zone_init(z);
 #endif
 
-       return(z);
+#if     CONFIG_ZCACHE
+       /* Check if boot-arg specified it should have a cache */
+       if (cache_all_zones || track_this_zone(name, cache_zone_name)) {
+               zone_change(z, Z_CACHING_ENABLED, TRUE);
+       }
+#endif
+
+       return z;
 }
-unsigned       zone_replenish_loops, zone_replenish_wakeups, zone_replenish_wakeups_initiated, zone_replenish_throttle_count;
+unsigned        zone_replenish_loops, zone_replenish_wakeups, zone_replenish_wakeups_initiated, zone_replenish_throttle_count;
 
 static void zone_replenish_thread(zone_t);
 
 /* High priority VM privileged thread used to asynchronously refill a designated
  * zone, such as the reserved VM map entry zone.
  */
-__attribute__((noreturn))
+__dead2
 static void
 zone_replenish_thread(zone_t z)
 {
@@ -2392,18 +2590,24 @@ zone_replenish_thread(zone_t z)
                        assert(z->async_prio_refill == TRUE);
 
                        unlock_zone(z);
-                       int     zflags = KMA_KOBJECT|KMA_NOPAGEWAIT;
+                       int     zflags = KMA_KOBJECT | KMA_NOPAGEWAIT;
                        vm_offset_t space, alloc_size;
                        kern_return_t kr;
-                               
-                       if (vm_pool_low())
+
+                       if (vm_pool_low()) {
                                alloc_size = round_page(z->elem_size);
-                       else
+                       } else {
                                alloc_size = z->alloc_size;
-                               
-                       if (z->noencrypt)
+                       }
+
+                       if (z->noencrypt) {
                                zflags |= KMA_NOENCRYPT;
-                               
+                       }
+
+                       if (z->clear_memory) {
+                               zflags |= KMA_ZERO;
+                       }
+
                        /* Trigger jetsams via the vm_pageout_garbage_collect thread if we're running out of zone memory */
                        if (is_zone_map_nearing_exhaustion()) {
                                thread_wakeup((event_t) &vm_pageout_garbage_collect);
@@ -2444,7 +2648,8 @@ zone_replenish_thread(zone_t z)
 }
 
 void
-zone_prio_refill_configure(zone_t z, vm_size_t low_water_mark) {
+zone_prio_refill_configure(zone_t z, vm_size_t low_water_mark)
+{
        z->prio_refill_watermark = low_water_mark;
 
        z->async_prio_refill = TRUE;
@@ -2482,12 +2687,20 @@ zdestroy(zone_t z)
         */
        z->zone_valid = FALSE;
 #endif
+       z->zone_destruction = TRUE;
        unlock_zone(z);
 
+#if CONFIG_ZCACHE
+       /* Drain the per-cpu caches if caching is enabled for the zone. */
+       if (zone_caching_enabled(z)) {
+               panic("zdestroy: Zone caching enabled for zone %s", z->zone_name);
+       }
+#endif /* CONFIG_ZCACHE */
+
        /* Dump all the free elements */
        drop_free_elements(z);
 
-#if    CONFIG_GZALLOC
+#if     CONFIG_GZALLOC
        /* If the zone is gzalloc managed dump all the elements in the free cache */
        gzalloc_empty_free_cache(z);
 #endif
@@ -2512,7 +2725,7 @@ zdestroy(zone_t z)
 
        unlock_zone(z);
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
 
        assert(!bitmap_test(zone_empty_bitmap, zindex));
        /* Mark the zone as empty in the bitmap */
@@ -2543,29 +2756,30 @@ zcram_metadata_init(vm_offset_t newmem, vm_size_t size, struct zone_page_metadat
        return;
 }
 
+
 static void
 random_free_to_zone(
-                       zone_t          zone,
-                       vm_offset_t     newmem,
-                       vm_offset_t     first_element_offset,
-                       int             element_count,
-                       unsigned int    *entropy_buffer)
+       zone_t          zone,
+       vm_offset_t     newmem,
+       vm_offset_t     first_element_offset,
+       int             element_count,
+       unsigned int    *entropy_buffer)
 {
-       vm_offset_t     last_element_offset;
-       vm_offset_t     element_addr;
+       vm_offset_t     last_element_offset;
+       vm_offset_t     element_addr;
        vm_size_t       elem_size;
-       int             index;
+       int             index;
 
-       assert(element_count  <= ZONE_CHUNK_MAXELEMENTS);
+       assert(element_count && element_count <= ZONE_CHUNK_MAXELEMENTS);
        elem_size = zone->elem_size;
        last_element_offset = first_element_offset + ((element_count * elem_size) - elem_size);
        for (index = 0; index < element_count; index++) {
                assert(first_element_offset <= last_element_offset);
                if (
 #if DEBUG || DEVELOPMENT
-               leak_scan_debug_flag || __improbable(zone->tags) ||
+                       leak_scan_debug_flag || __improbable(zone->tags) ||
 #endif /* DEBUG || DEVELOPMENT */
-               random_bool_gen_bits(&zone_bool_gen, entropy_buffer, MAX_ENTROPY_PER_ZCRAM, 1)) {
+                       random_bool_gen_bits(&zone_bool_gen, entropy_buffer, MAX_ENTROPY_PER_ZCRAM, 1)) {
                        element_addr = newmem + first_element_offset;
                        first_element_offset += elem_size;
                } else {
@@ -2585,11 +2799,11 @@ random_free_to_zone(
  */
 void
 zcram(
-       zone_t          zone,
-       vm_offset_t                     newmem,
-       vm_size_t               size)
+       zone_t          zone,
+       vm_offset_t                     newmem,
+       vm_size_t               size)
 {
-       vm_size_t       elem_size;
+       vm_size_t       elem_size;
        boolean_t   from_zm = FALSE;
        int element_count;
        unsigned int entropy_buffer[MAX_ENTROPY_PER_ZCRAM] = { 0 };
@@ -2597,14 +2811,15 @@ zcram(
        /* Basic sanity checks */
        assert(zone != ZONE_NULL && newmem != (vm_offset_t)0);
        assert(!zone->collectable || zone->allows_foreign
-               || (from_zone_map(newmem, size)));
+           || (from_zone_map(newmem, size)));
 
        elem_size = zone->elem_size;
 
        KDBG(MACHDBG_CODE(DBG_MACH_ZALLOC, ZALLOC_ZCRAM) | DBG_FUNC_START, zone->index, size);
 
-       if (from_zone_map(newmem, size))
+       if (from_zone_map(newmem, size)) {
                from_zm = TRUE;
+       }
 
        if (!from_zm) {
                /* We cannot support elements larger than page size for foreign memory because we
@@ -2614,9 +2829,12 @@ zcram(
                assert((zone->allows_foreign == TRUE) && (zone->elem_size <= (PAGE_SIZE - sizeof(struct zone_page_metadata))));
        }
 
-       if (zalloc_debug & ZALLOC_DEBUG_ZCRAM)
+#if DEBUG || DEVELOPMENT
+       if (zalloc_debug & ZALLOC_DEBUG_ZCRAM) {
                kprintf("zcram(%p[%s], 0x%lx%s, 0x%lx)\n", zone, zone->zone_name,
-                               (unsigned long)newmem, from_zm ? "" : "[F]", (unsigned long)size);
+                   (unsigned long)newmem, from_zm ? "" : "[F]", (unsigned long)size);
+       }
+#endif /* DEBUG || DEVELOPMENT */
 
        ZONE_PAGE_COUNT_INCR(zone, (size / PAGE_SIZE));
 
@@ -2643,10 +2861,10 @@ zcram(
        zcram_metadata_init(newmem, size, chunk_metadata);
 
 #if VM_MAX_TAG_ZONES
-    if (__improbable(zone->tags)) {
-        assert(from_zm);
-        ztMemoryAdd(zone, newmem, size);
-    }
+       if (__improbable(zone->tags)) {
+               assert(from_zm);
+               ztMemoryAdd(zone, newmem, size);
+       }
 #endif /* VM_MAX_TAG_ZONES */
 
        lock_zone(zone);
@@ -2654,29 +2872,28 @@ zcram(
        enqueue_tail(&zone->pages.all_used, &(chunk_metadata->pages));
 
        if (!from_zm) {
-               /* We cannot support elements larger than page size for foreign memory because we 
-                * put metadata on the page itself for each page of foreign memory. We need to do 
-                * this in order to be able to reach the metadata when any element is freed 
+               /* We cannot support elements larger than page size for foreign memory because we
+                * put metadata on the page itself for each page of foreign memory. We need to do
+                * this in order to be able to reach the metadata when any element is freed
                 */
 
                for (; size > 0; newmem += PAGE_SIZE, size -= PAGE_SIZE) {
                        vm_offset_t first_element_offset = 0;
-                       if (zone_page_metadata_size % ZONE_ELEMENT_ALIGNMENT == 0){
+                       if (zone_page_metadata_size % ZONE_ELEMENT_ALIGNMENT == 0) {
                                first_element_offset = zone_page_metadata_size;
                        } else {
                                first_element_offset = zone_page_metadata_size + (ZONE_ELEMENT_ALIGNMENT - (zone_page_metadata_size % ZONE_ELEMENT_ALIGNMENT));
                        }
-                       element_count = (int)((PAGE_SIZE - first_element_offset) / elem_size);
-                       random_free_to_zone(zone, newmem, first_element_offset, element_count, entropy_buffer);                         
+                       element_count = (unsigned int)((PAGE_SIZE - first_element_offset) / elem_size);
+                       random_free_to_zone(zone, newmem, first_element_offset, element_count, entropy_buffer);
                }
        } else {
-               element_count = (int)(size / elem_size);
-               random_free_to_zone(zone, newmem, 0, element_count, entropy_buffer);    
+               element_count = (unsigned int)(size / elem_size);
+               random_free_to_zone(zone, newmem, 0, element_count, entropy_buffer);
        }
        unlock_zone(zone);
-       
-       KDBG(MACHDBG_CODE(DBG_MACH_ZALLOC, ZALLOC_ZCRAM) | DBG_FUNC_END, zone->index);
 
+       KDBG(MACHDBG_CODE(DBG_MACH_ZALLOC, ZALLOC_ZCRAM) | DBG_FUNC_END, zone->index);
 }
 
 /*
@@ -2687,15 +2904,20 @@ zcram(
  */
 int
 zfill(
-       zone_t  zone,
-       int     nelem)
+       zone_t  zone,
+       int     nelem)
 {
        kern_return_t kr;
-       vm_offset_t     memory;
+       vm_offset_t     memory;
 
        vm_size_t alloc_size = zone->alloc_size;
        vm_size_t elem_per_alloc = alloc_size / zone->elem_size;
        vm_size_t nalloc = (nelem + elem_per_alloc - 1) / elem_per_alloc;
+       int zflags = KMA_KOBJECT;
+
+       if (zone->clear_memory) {
+               zflags |= KMA_ZERO;
+       }
 
        /* Don't mix-and-match zfill with foreign memory */
        assert(!zone->allows_foreign);
@@ -2705,10 +2927,10 @@ zfill(
                thread_wakeup((event_t) &vm_pageout_garbage_collect);
        }
 
-       kr = kernel_memory_allocate(zone_map, &memory, nalloc * alloc_size, 0, KMA_KOBJECT, VM_KERN_MEMORY_ZONE);
+       kr = kernel_memory_allocate(zone_map, &memory, nalloc * alloc_size, 0, zflags, VM_KERN_MEMORY_ZONE);
        if (kr != KERN_SUCCESS) {
                printf("%s: kernel_memory_allocate() of %lu bytes failed\n",
-                               __func__, (unsigned long)(nalloc * alloc_size));
+                   __func__, (unsigned long)(nalloc * alloc_size));
                return 0;
        }
 
@@ -2729,8 +2951,11 @@ zone_bootstrap(void)
 {
        char temp_buf[16];
 
-       if (!PE_parse_boot_argn("zalloc_debug", &zalloc_debug, sizeof(zalloc_debug)))
+#if DEBUG || DEVELOPMENT
+       if (!PE_parse_boot_argn("zalloc_debug", &zalloc_debug, sizeof(zalloc_debug))) {
                zalloc_debug = 0;
+       }
+#endif /* DEBUG || DEVELOPMENT */
 
        /* Set up zone element poisoning */
        zp_init();
@@ -2740,9 +2965,13 @@ zone_bootstrap(void)
        /* should zlog log to debug zone corruption instead of leaks? */
        if (PE_parse_boot_argn("-zc", temp_buf, sizeof(temp_buf))) {
                corruption_debug_flag = TRUE;
-       }       
+       }
 
 #if DEBUG || DEVELOPMENT
+       /* should perform zone element size checking in copyin/copyout? */
+       if (PE_parse_boot_argn("-no-copyio-zalloc-check", temp_buf, sizeof(temp_buf))) {
+               copyio_zalloc_check = FALSE;
+       }
 #if VM_MAX_TAG_ZONES
        /* enable tags for zones that ask for  */
        if (PE_parse_boot_argn("-zt", temp_buf, sizeof(temp_buf))) {
@@ -2773,8 +3002,21 @@ zone_bootstrap(void)
        lck_grp_attr_setdefault(&zone_locks_grp_attr);
        lck_grp_init(&zone_locks_grp, "zone_locks", &zone_locks_grp_attr);
 
-       lck_attr_setdefault(&zone_metadata_lock_attr); 
+       lck_attr_setdefault(&zone_metadata_lock_attr);
        lck_mtx_init_ext(&zone_metadata_region_lck, &zone_metadata_region_lck_ext, &zone_locks_grp, &zone_metadata_lock_attr);
+
+#if     CONFIG_ZCACHE
+       /* zcc_enable_for_zone_name=<zone>: enable per-cpu zone caching for <zone>. */
+       if (PE_parse_boot_arg_str("zcc_enable_for_zone_name", cache_zone_name, sizeof(cache_zone_name))) {
+               printf("zcache: caching enabled for zone %s\n", cache_zone_name);
+       }
+
+       /* -zcache_all: enable per-cpu zone caching for all zones, overrides 'zcc_enable_for_zone_name'. */
+       if (PE_parse_boot_argn("-zcache_all", temp_buf, sizeof(temp_buf))) {
+               cache_all_zones = TRUE;
+               printf("zcache: caching enabled for all zones\n");
+       }
+#endif /* CONFIG_ZCACHE */
 }
 
 /*
@@ -2800,20 +3042,23 @@ extern pid_t find_largest_process_vm_map_entries(void);
  */
 boolean_t memorystatus_kill_on_zone_map_exhaustion(pid_t pid);
 
-void get_zone_map_size(uint64_t *current_size, uint64_t *capacity)
+void
+get_zone_map_size(uint64_t *current_size, uint64_t *capacity)
 {
        *current_size = zone_map->size;
        *capacity = vm_map_max(zone_map) - vm_map_min(zone_map);
 }
 
-void get_largest_zone_info(char *zone_name, size_t zone_name_len, uint64_t *zone_size)
+void
+get_largest_zone_info(char *zone_name, size_t zone_name_len, uint64_t *zone_size)
 {
        zone_t largest_zone = zone_find_largest();
        strlcpy(zone_name, largest_zone->zone_name, zone_name_len);
        *zone_size = largest_zone->cur_size;
 }
 
-boolean_t is_zone_map_nearing_exhaustion(void)
+boolean_t
+is_zone_map_nearing_exhaustion(void)
 {
        uint64_t size = zone_map->size;
        uint64_t capacity = vm_map_max(zone_map) - vm_map_min(zone_map);
@@ -2832,13 +3077,14 @@ extern zone_t vm_object_zone;
  * Tries to kill a single process if it can attribute one to the largest zone. If not, wakes up the memorystatus thread
  * to walk through the jetsam priority bands and kill processes.
  */
-static void kill_process_in_largest_zone(void)
+static void
+kill_process_in_largest_zone(void)
 {
        pid_t pid = -1;
        zone_t largest_zone = zone_find_largest();
 
        printf("zone_map_exhaustion: Zone map size %lld, capacity %lld [jetsam limit %d%%]\n", (uint64_t)zone_map->size,
-                       (uint64_t)(vm_map_max(zone_map) - vm_map_min(zone_map)), zone_map_jetsam_limit);
+           (uint64_t)(vm_map_max(zone_map) - vm_map_min(zone_map)), zone_map_jetsam_limit);
        printf("zone_map_exhaustion: Largest zone %s, size %lu\n", largest_zone->zone_name, (uintptr_t)largest_zone->cur_size);
 
        /*
@@ -2852,8 +3098,8 @@ static void kill_process_in_largest_zone(void)
         * vm_map_entry_zone as the largest. This lets us target a specific process to jetsam to quickly recover from the zone map bloat.
         */
        if (largest_zone == vm_object_zone) {
-               int vm_object_zone_count = vm_object_zone->count;
-               int vm_map_entry_zone_count = vm_map_entry_zone->count;
+               unsigned int vm_object_zone_count = vm_object_zone->count;
+               unsigned int vm_map_entry_zone_count = vm_map_entry_zone->count;
                /* Is the VM map entries zone count >= 98% of the VM objects zone count? */
                if (vm_map_entry_zone_count >= ((vm_object_zone_count * VMENTRY_TO_VMOBJECT_COMPARISON_RATIO) / 100)) {
                        largest_zone = vm_map_entry_zone;
@@ -2879,29 +3125,34 @@ void
 zone_init(
        vm_size_t max_zonemap_size)
 {
-       kern_return_t   retval;
-       vm_offset_t     zone_min;
-       vm_offset_t     zone_max;
-       vm_offset_t     zone_metadata_space;
-       unsigned int    zone_pages;
+       kern_return_t   retval;
+       vm_offset_t     zone_min;
+       vm_offset_t     zone_max;
+       vm_offset_t     zone_metadata_space;
+       unsigned int    zone_pages;
        vm_map_kernel_flags_t vmk_flags;
 
 #if VM_MAX_TAG_ZONES
-    if (zone_tagging_on) ztInit(max_zonemap_size, &zone_locks_grp);
+       if (zone_tagging_on) {
+               ztInit(max_zonemap_size, &zone_locks_grp);
+       }
 #endif
 
        vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
        vmk_flags.vmkf_permanent = TRUE;
        retval = kmem_suballoc(kernel_map, &zone_min, max_zonemap_size,
-                              FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_ZONE,
-                              &zone_map);
+           FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_ZONE,
+           &zone_map);
 
-       if (retval != KERN_SUCCESS)
+       if (retval != KERN_SUCCESS) {
                panic("zone_init: kmem_suballoc failed");
+       }
        zone_max = zone_min + round_page(max_zonemap_size);
-#if    CONFIG_GZALLOC
+
+#if     CONFIG_GZALLOC
        gzalloc_init(max_zonemap_size);
 #endif
+
        /*
         * Setup garbage collection information:
         */
@@ -2911,9 +3162,10 @@ zone_init(
        zone_pages = (unsigned int)atop_kernel(zone_max - zone_min);
        zone_metadata_space = round_page(zone_pages * sizeof(struct zone_page_metadata));
        retval = kernel_memory_allocate(zone_map, &zone_metadata_region_min, zone_metadata_space,
-                                       0, KMA_KOBJECT | KMA_VAONLY | KMA_PERMANENT, VM_KERN_MEMORY_OSFMK);
-       if (retval != KERN_SUCCESS)
+           0, KMA_KOBJECT | KMA_VAONLY | KMA_PERMANENT, VM_KERN_MEMORY_OSFMK);
+       if (retval != KERN_SUCCESS) {
                panic("zone_init: zone_metadata_region initialization failed!");
+       }
        zone_metadata_region_max = zone_metadata_region_min + zone_metadata_space;
 
 #if defined(__LP64__)
@@ -2922,18 +3174,20 @@ zone_init(
         * the vm_page zone can be packed properly (see vm_page.h
         * for the packing requirements
         */
-       if ((vm_page_t)(VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(zone_metadata_region_max))) != (vm_page_t)zone_metadata_region_max)
+       if ((vm_page_t)(VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(zone_metadata_region_max))) != (vm_page_t)zone_metadata_region_max) {
                panic("VM_PAGE_PACK_PTR failed on zone_metadata_region_max - %p", (void *)zone_metadata_region_max);
+       }
 
-       if ((vm_page_t)(VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(zone_map_max_address))) != (vm_page_t)zone_map_max_address)
+       if ((vm_page_t)(VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(zone_map_max_address))) != (vm_page_t)zone_map_max_address) {
                panic("VM_PAGE_PACK_PTR failed on zone_map_max_address - %p", (void *)zone_map_max_address);
+       }
 #endif
 
        lck_grp_attr_setdefault(&zone_gc_lck_grp_attr);
        lck_grp_init(&zone_gc_lck_grp, "zone_gc", &zone_gc_lck_grp_attr);
        lck_attr_setdefault(&zone_gc_lck_attr);
        lck_mtx_init_ext(&zone_gc_lock, &zone_gc_lck_ext, &zone_gc_lck_grp, &zone_gc_lck_attr);
-       
+
 #if CONFIG_ZLEAKS
        /*
         * Initialize the zone leak monitor
@@ -2942,48 +3196,93 @@ zone_init(
 #endif /* CONFIG_ZLEAKS */
 
 #if VM_MAX_TAG_ZONES
-       if (zone_tagging_on) vm_allocation_zones_init();
+       if (zone_tagging_on) {
+               vm_allocation_zones_init();
+       }
 #endif
 
        int jetsam_limit_temp = 0;
-       if (PE_parse_boot_argn("zone_map_jetsam_limit", &jetsam_limit_temp, sizeof (jetsam_limit_temp)) &&
-                       jetsam_limit_temp > 0 && jetsam_limit_temp <= 100)
+       if (PE_parse_boot_argn("zone_map_jetsam_limit", &jetsam_limit_temp, sizeof(jetsam_limit_temp)) &&
+           jetsam_limit_temp > 0 && jetsam_limit_temp <= 100) {
                zone_map_jetsam_limit = jetsam_limit_temp;
+       }
 }
 
-extern volatile SInt32 kfree_nop_count;
-
 #pragma mark -
 #pragma mark zalloc_canblock
 
 extern boolean_t early_boot_complete;
 
+void
+zalloc_poison_element(boolean_t check_poison, zone_t zone, vm_offset_t addr)
+{
+       vm_offset_t     inner_size = zone->elem_size;
+       if (__improbable(check_poison && addr)) {
+               vm_offset_t *element_cursor  = ((vm_offset_t *) addr) + 1;
+               vm_offset_t *backup  = get_backup_ptr(inner_size, (vm_offset_t *) addr);
+
+               for (; element_cursor < backup; element_cursor++) {
+                       if (__improbable(*element_cursor != ZP_POISON)) {
+                               zone_element_was_modified_panic(zone,
+                                   addr,
+                                   *element_cursor,
+                                   ZP_POISON,
+                                   ((vm_offset_t)element_cursor) - addr);
+                       }
+               }
+       }
+
+       if (addr) {
+               /*
+                * Clear out the old next pointer and backup to avoid leaking the cookie
+                * and so that only values on the freelist have a valid cookie
+                */
+
+               vm_offset_t *primary  = (vm_offset_t *) addr;
+               vm_offset_t *backup   = get_backup_ptr(inner_size, primary);
+
+               *primary = ZP_POISON;
+               *backup  = ZP_POISON;
+       }
+}
+
+/*
+ * When deleting page mappings from the kernel map, it might be necessary to split
+ * apart an existing vm_map_entry. That means that a "free" operation, will need to
+ * *allocate* new vm_map_entry structures before it can free a page.
+ *
+ * This reserve here is the number of elements which are held back from everyone except
+ * the zone_gc thread. This is done so the zone_gc thread should never have to wait for
+ * the zone replenish thread for vm_map_entry structs. If it did, it could wind up
+ * in a deadlock.
+ */
+#define VM_MAP_ENTRY_RESERVE_CNT 8
+
 /*
  *     zalloc returns an element from the specified zone.
  */
 static void *
 zalloc_internal(
-       zone_t  zone,
+       zone_t  zone,
        boolean_t canblock,
        boolean_t nopagewait,
        vm_size_t
 #if !VM_MAX_TAG_ZONES
-    __unused
+       __unused
 #endif
-    reqsize,
+       reqsize,
        vm_tag_t  tag)
 {
-       vm_offset_t     addr = 0;
-       kern_return_t   retval;
-       uintptr_t       zbt[MAX_ZTRACE_DEPTH];  /* used in zone leak logging and zone leak detection */
-       int             numsaved = 0;
-       boolean_t       zone_replenish_wakeup = FALSE, zone_alloc_throttle = FALSE;
-       thread_t thr = current_thread();
+       vm_offset_t     addr = 0;
+       kern_return_t   retval;
+       uintptr_t       zbt[MAX_ZTRACE_DEPTH];  /* used in zone leak logging and zone leak detection */
+       unsigned int    numsaved = 0;
+       thread_t        thr = current_thread();
        boolean_t       check_poison = FALSE;
        boolean_t       set_doing_alloc_with_vm_priv = FALSE;
 
 #if CONFIG_ZLEAKS
-       uint32_t        zleak_tracedepth = 0;  /* log this allocation if nonzero */
+       uint32_t        zleak_tracedepth = 0;  /* log this allocation if nonzero */
 #endif /* CONFIG_ZLEAKS */
 
 #if KASAN
@@ -3004,14 +3303,15 @@ zalloc_internal(
        assert(zone != ZONE_NULL);
        assert(irq_safe || ml_get_interrupts_enabled() || ml_is_quiescing() || debug_mode_active() || !early_boot_complete);
 
-#if    CONFIG_GZALLOC
+#if     CONFIG_GZALLOC
        addr = gzalloc_alloc(zone, canblock);
 #endif
        /*
         * If zone logging is turned on and this is the zone we're tracking, grab a backtrace.
         */
-       if (__improbable(DO_LOGGING(zone)))
-               numsaved = OSBacktrace((void*) zbt, MAX_ZTRACE_DEPTH);
+       if (__improbable(DO_LOGGING(zone))) {
+               numsaved = OSBacktrace((void*) zbt, MAX_ZTRACE_DEPTH);
+       }
 
 #if CONFIG_ZLEAKS
        /*
@@ -3020,79 +3320,112 @@ zalloc_internal(
         */
        if (__improbable(zone->zleak_on && sample_counter(&zone->zleak_capture, zleak_sample_factor) == TRUE)) {
                /* Avoid backtracing twice if zone logging is on */
-               if (numsaved == 0)
-                       zleak_tracedepth = backtrace(zbt, MAX_ZTRACE_DEPTH);
-               else
+               if (numsaved == 0) {
+                       zleak_tracedepth = backtrace(zbt, MAX_ZTRACE_DEPTH, NULL);
+               } else {
                        zleak_tracedepth = numsaved;
+               }
        }
 #endif /* CONFIG_ZLEAKS */
 
 #if VM_MAX_TAG_ZONES
-       if (__improbable(zone->tags)) vm_tag_will_update_zone(tag, zone->tag_zone_index);
+       if (__improbable(zone->tags)) {
+               vm_tag_will_update_zone(tag, zone->tag_zone_index);
+       }
 #endif /* VM_MAX_TAG_ZONES */
 
+#if CONFIG_ZCACHE
+       if (__probable(addr == 0)) {
+               if (zone_caching_enabled(zone)) {
+                       addr = zcache_alloc_from_cpu_cache(zone);
+                       if (addr) {
+#if KASAN_ZALLOC
+                               addr = kasan_fixup_allocated_element_address(zone, addr);
+#endif
+                               if (__improbable(DO_LOGGING(zone) && addr)) {
+                                       btlog_add_entry(zone->zlog_btlog, (void *)addr,
+                                           ZOP_ALLOC, (void **)zbt, numsaved);
+                               }
+                               DTRACE_VM2(zalloc, zone_t, zone, void*, addr);
+                               return (void *)addr;
+                       }
+               }
+       }
+#endif /* CONFIG_ZCACHE */
+
        lock_zone(zone);
        assert(zone->zone_valid);
 
+       /*
+        * Check if we need another thread to replenish the zone.
+        * This is used for elements, like vm_map_entry, which are
+        * needed themselves to implement zalloc().
+        */
        if (zone->async_prio_refill && zone->zone_replenish_thread) {
-                       vm_size_t zfreec = (zone->cur_size - (zone->count * zone->elem_size));
-                       vm_size_t zrefillwm = zone->prio_refill_watermark * zone->elem_size;
-                       zone_replenish_wakeup = (zfreec < zrefillwm);
-                       zone_alloc_throttle = (((zfreec < (zrefillwm / 2)) && ((thr->options & TH_OPT_VMPRIV) == 0)) || (zfreec == 0));
-
-                       do {
-                           if (zone_replenish_wakeup) {
-                                   zone_replenish_wakeups_initiated++;
-                                   /* Signal the potentially waiting
-                                    * refill thread.
-                                    */
-                                   thread_wakeup(&zone->zone_replenish_thread);
-
-                                       /* We don't want to wait around for zone_replenish_thread to bump up the free count
-                                        * if we're in zone_gc(). This keeps us from deadlocking with zone_replenish_thread.
-                                        */
-                                       if (thr->options & TH_OPT_ZONE_GC)
-                                               break;
+               vm_size_t curr_free;
+               vm_size_t refill_level;
+               const vm_size_t reserved_min = VM_MAP_ENTRY_RESERVE_CNT * zone->elem_size;
+
+               for (;;) {
+                       curr_free = (zone->cur_size - (zone->count * zone->elem_size));
+                       refill_level = zone->prio_refill_watermark * zone->elem_size;
+
+                       /*
+                        * Nothing to do if there are plenty of elements.
+                        */
+                       if (curr_free > refill_level) {
+                               break;
+                       }
+
+                       /*
+                        * Wakeup the replenish thread.
+                        */
+                       zone_replenish_wakeups_initiated++;
+                       thread_wakeup(&zone->zone_replenish_thread);
+
+                       /*
+                        * If we:
+                        * - still have head room, more than half the refill amount, or
+                        * - this is a VMPRIV thread and we're still above reserved, or
+                        * - this is the zone garbage collection thread which may use the reserve
+                        * then we don't have to wait for the replenish thread.
+                        *
+                        * The reserve for the garbage collection thread is to avoid a deadlock
+                        * on the zone_map_lock between the replenish thread and GC thread.
+                        */
+                       if (curr_free > refill_level / 2 ||
+                           ((thr->options & TH_OPT_VMPRIV) && curr_free > reserved_min) ||
+                           (thr->options & TH_OPT_ZONE_GC)) {
+                               break;
+                       }
+                       zone_replenish_throttle_count++;
+                       unlock_zone(zone);
+                       assert_wait_timeout(zone, THREAD_UNINT, 1, NSEC_PER_MSEC);
+                       thread_block(THREAD_CONTINUE_NULL);
+                       lock_zone(zone);
+
+                       assert(zone->zone_valid);
+               }
+       }
 
-                                   unlock_zone(zone);
-                                   /* Scheduling latencies etc. may prevent
-                                    * the refill thread from keeping up
-                                    * with demand. Throttle consumers
-                                    * when we fall below half the
-                                    * watermark, unless VM privileged
-                                    */
-                                   if (zone_alloc_throttle) {
-                                           zone_replenish_throttle_count++;
-                                           assert_wait_timeout(zone, THREAD_UNINT, 1, NSEC_PER_MSEC);
-                                           thread_block(THREAD_CONTINUE_NULL);
-                                   }
-                                   lock_zone(zone);
-                                       assert(zone->zone_valid);
-                           }
-
-                               zfreec = (zone->cur_size - (zone->count * zone->elem_size));
-                               zrefillwm = zone->prio_refill_watermark * zone->elem_size;
-                               zone_replenish_wakeup = (zfreec < zrefillwm);
-                               zone_alloc_throttle = (((zfreec < (zrefillwm / 2)) && ((thr->options & TH_OPT_VMPRIV) == 0)) || (zfreec == 0));
-
-                   } while (zone_alloc_throttle == TRUE);
-       }
-       
-       if (__probable(addr == 0))
+       if (__probable(addr == 0)) {
                addr = try_alloc_from_zone(zone, tag, &check_poison);
+       }
 
        /* If we're here because of zone_gc(), we didn't wait for zone_replenish_thread to finish.
         * So we need to ensure that we did successfully grab an element. And we only need to assert
         * this for zones that have a replenish thread configured (in this case, the Reserved VM map
-        * entries zone).
+        * entries zone). The value of reserved_min in the previous bit of code should have given us
+        * headroom even though the GC thread didn't wait.
         */
-       if (thr->options & TH_OPT_ZONE_GC && zone->async_prio_refill)
+       if ((thr->options & TH_OPT_ZONE_GC) && zone->async_prio_refill) {
                assert(addr != 0);
+       }
 
        while ((addr == 0) && canblock) {
                /*
-                * zone is empty, try to expand it
-                * 
+                * zone is empty, try to expand it
+                *
                 * Note that we now allow up to 2 threads (1 vm_privliged and 1 non-vm_privliged)
                 * to expand the zone concurrently...  this is necessary to avoid stalling
                 * vm_privileged threads running critical code necessary to continue compressing/swapping
@@ -3120,8 +3453,9 @@ zalloc_internal(
 
                        if ((zone->cur_size + zone->elem_size) >
                            zone->max_size) {
-                               if (zone->exhaustible)
+                               if (zone->exhaustible) {
                                        break;
+                               }
                                if (zone->expandable) {
                                        /*
                                         * We're willing to overflow certain
@@ -3131,7 +3465,7 @@ zalloc_internal(
                                         * with the collectable flag. What we
                                         * want is an assurance we can get the
                                         * memory back, assuming there's no
-                                        * leak. 
+                                        * leak.
                                         */
                                        zone->max_size += (zone->max_size >> 1);
                                } else {
@@ -3139,40 +3473,47 @@ zalloc_internal(
 
                                        panic_include_zprint = TRUE;
 #if CONFIG_ZLEAKS
-                                       if (zleak_state & ZLEAK_STATE_ACTIVE)
+                                       if (zleak_state & ZLEAK_STATE_ACTIVE) {
                                                panic_include_ztrace = TRUE;
+                                       }
 #endif /* CONFIG_ZLEAKS */
                                        panic("zalloc: zone \"%s\" empty.", zone->zone_name);
                                }
                        }
-                       /* 
+                       /*
                         * It is possible that a BG thread is refilling/expanding the zone
                         * and gets pre-empted during that operation. That blocks all other
                         * threads from making progress leading to a watchdog timeout. To
                         * avoid that, boost the thread priority using the rwlock boost
                         */
                        set_thread_rwlock_boost();
-                       
+
                        if ((thr->options & TH_OPT_VMPRIV)) {
-                               zone->doing_alloc_with_vm_priv = TRUE;
+                               zone->doing_alloc_with_vm_priv = TRUE;
                                set_doing_alloc_with_vm_priv = TRUE;
                        } else {
-                               zone->doing_alloc_without_vm_priv = TRUE;
+                               zone->doing_alloc_without_vm_priv = TRUE;
                        }
                        unlock_zone(zone);
 
                        for (;;) {
-                               int     zflags = KMA_KOBJECT|KMA_NOPAGEWAIT;
+                               int     zflags = KMA_KOBJECT | KMA_NOPAGEWAIT;
 
-                               if (vm_pool_low() || retry >= 1)
-                                       alloc_size = 
-                                               round_page(zone->elem_size);
-                               else
+                               if (vm_pool_low() || retry >= 1) {
+                                       alloc_size =
+                                           round_page(zone->elem_size);
+                               } else {
                                        alloc_size = zone->alloc_size;
-                               
-                               if (zone->noencrypt)
+                               }
+
+                               if (zone->noencrypt) {
                                        zflags |= KMA_NOENCRYPT;
-                               
+                               }
+
+                               if (zone->clear_memory) {
+                                       zflags |= KMA_ZERO;
+                               }
+
                                /* Trigger jetsams via the vm_pageout_garbage_collect thread if we're running out of zone memory */
                                if (is_zone_map_nearing_exhaustion()) {
                                        thread_wakeup((event_t) &vm_pageout_garbage_collect);
@@ -3184,41 +3525,40 @@ zalloc_internal(
                                        if ((zleak_state & (ZLEAK_STATE_ENABLED | ZLEAK_STATE_ACTIVE)) == ZLEAK_STATE_ENABLED) {
                                                if (zone_map->size >= zleak_global_tracking_threshold) {
                                                        kern_return_t kr;
-                                                       
+
                                                        kr = zleak_activate();
                                                        if (kr != KERN_SUCCESS) {
                                                                printf("Failed to activate live zone leak debugging (%d).\n", kr);
                                                        }
                                                }
                                        }
-                                       
+
                                        if ((zleak_state & ZLEAK_STATE_ACTIVE) && !(zone->zleak_on)) {
                                                if (zone->cur_size > zleak_per_zone_tracking_threshold) {
                                                        zone->zleak_on = TRUE;
-                                               }       
+                                               }
                                        }
 #endif /* CONFIG_ZLEAKS */
                                        zcram(zone, space, alloc_size);
-                                       
+
                                        break;
                                } else if (retval != KERN_RESOURCE_SHORTAGE) {
                                        retry++;
-                                       
+
                                        if (retry == 3) {
                                                panic_include_zprint = TRUE;
 #if CONFIG_ZLEAKS
                                                if ((zleak_state & ZLEAK_STATE_ACTIVE)) {
                                                        panic_include_ztrace = TRUE;
                                                }
-#endif /* CONFIG_ZLEAKS */             
+#endif /* CONFIG_ZLEAKS */
                                                if (retval == KERN_NO_SPACE) {
                                                        zone_t zone_largest = zone_find_largest();
                                                        panic("zalloc: zone map exhausted while allocating from zone %s, likely due to memory leak in zone %s (%lu total bytes, %d elements allocated)",
-                                                       zone->zone_name, zone_largest->zone_name,
-                                                       (unsigned long)zone_largest->cur_size, zone_largest->count);
-
+                                                           zone->zone_name, zone_largest->zone_name,
+                                                           (unsigned long)zone_largest->cur_size, zone_largest->count);
                                                }
-                                               panic("zalloc: \"%s\" (%d elements) retry fail %d, kfree_nop_count: %d", zone->zone_name, zone->count, retval, (int)kfree_nop_count);
+                                               panic("zalloc: \"%s\" (%d elements) retry fail %d", zone->zone_name, zone->count, retval);
                                        }
                                } else {
                                        break;
@@ -3227,13 +3567,14 @@ zalloc_internal(
                        lock_zone(zone);
                        assert(zone->zone_valid);
 
-                       if (set_doing_alloc_with_vm_priv == TRUE)
-                               zone->doing_alloc_with_vm_priv = FALSE;
-                       else
-                               zone->doing_alloc_without_vm_priv = FALSE; 
-                       
+                       if (set_doing_alloc_with_vm_priv == TRUE) {
+                               zone->doing_alloc_with_vm_priv = FALSE;
+                       } else {
+                               zone->doing_alloc_without_vm_priv = FALSE;
+                       }
+
                        if (zone->waiting) {
-                               zone->waiting = FALSE;
+                               zone->waiting = FALSE;
                                zone_wakeup(zone);
                        }
                        clear_thread_rwlock_boost();
@@ -3241,8 +3582,9 @@ zalloc_internal(
                        addr = try_alloc_from_zone(zone, tag, &check_poison);
                        if (addr == 0 &&
                            retval == KERN_RESOURCE_SHORTAGE) {
-                               if (nopagewait == TRUE)
-                                       break;  /* out of the main while loop */
+                               if (nopagewait == TRUE) {
+                                       break;  /* out of the main while loop */
+                               }
                                unlock_zone(zone);
 
                                VM_PAGE_WAIT();
@@ -3250,24 +3592,25 @@ zalloc_internal(
                                assert(zone->zone_valid);
                        }
                }
-               if (addr == 0)
+               if (addr == 0) {
                        addr = try_alloc_from_zone(zone, tag, &check_poison);
+               }
        }
 
 #if CONFIG_ZLEAKS
        /* Zone leak detection:
-        * If we're sampling this allocation, add it to the zleaks hash table. 
+        * If we're sampling this allocation, add it to the zleaks hash table.
         */
-       if (addr && zleak_tracedepth > 0)  {
+       if (addr && zleak_tracedepth > 0) {
                /* Sampling can fail if another sample is happening at the same time in a different zone. */
                if (!zleak_log(zbt, addr, zleak_tracedepth, zone->elem_size)) {
                        /* If it failed, roll back the counter so we sample the next allocation instead. */
                        zone->zleak_capture = zleak_sample_factor;
                }
        }
-#endif /* CONFIG_ZLEAKS */                     
-                       
-                       
+#endif /* CONFIG_ZLEAKS */
+
+
        if ((addr == 0) && (!canblock || nopagewait) && (zone->async_pending == FALSE) && (zone->no_callout == FALSE) && (zone->exhaustible == FALSE) && (!vm_pool_low())) {
                zone->async_pending = TRUE;
                unlock_zone(zone);
@@ -3278,98 +3621,97 @@ zalloc_internal(
        }
 
 #if VM_MAX_TAG_ZONES
-    if (__improbable(zone->tags) && addr) {
-        if (reqsize) reqsize = zone->elem_size - reqsize;
-        vm_tag_update_zone_size(tag, zone->tag_zone_index, zone->elem_size, reqsize);
-    }
+       if (__improbable(zone->tags) && addr) {
+               if (reqsize) {
+                       reqsize = zone->elem_size - reqsize;
+               }
+               vm_tag_update_zone_size(tag, zone->tag_zone_index, zone->elem_size, reqsize);
+       }
 #endif /* VM_MAX_TAG_ZONES */
 
        unlock_zone(zone);
 
-       vm_offset_t     inner_size = zone->elem_size;
-
        if (__improbable(DO_LOGGING(zone) && addr)) {
                btlog_add_entry(zone->zlog_btlog, (void *)addr, ZOP_ALLOC, (void **)zbt, numsaved);
        }
 
-       if (__improbable(check_poison && addr)) {
-               vm_offset_t *element_cursor  = ((vm_offset_t *) addr) + 1;
-               vm_offset_t *backup  = get_backup_ptr(inner_size, (vm_offset_t *) addr);
-
-               for ( ; element_cursor < backup ; element_cursor++)
-                       if (__improbable(*element_cursor != ZP_POISON))
-                               zone_element_was_modified_panic(zone,
-                                                               addr,
-                                                               *element_cursor,
-                                                               ZP_POISON,
-                                                               ((vm_offset_t)element_cursor) - addr);
-       }
+       zalloc_poison_element(check_poison, zone, addr);
 
        if (addr) {
-               /*
-                * Clear out the old next pointer and backup to avoid leaking the cookie
-                * and so that only values on the freelist have a valid cookie
-                */
-
-               vm_offset_t *primary  = (vm_offset_t *) addr;
-               vm_offset_t *backup   = get_backup_ptr(inner_size, primary);
-
-               *primary = ZP_POISON;
-               *backup  = ZP_POISON;
-
 #if DEBUG || DEVELOPMENT
                if (__improbable(leak_scan_debug_flag && !(zone->elem_size & (sizeof(uintptr_t) - 1)))) {
-                       int count, idx;
+                       unsigned int count, idx;
                        /* Fill element, from tail, with backtrace in reverse order */
-                       if (numsaved == 0) numsaved = backtrace(zbt, MAX_ZTRACE_DEPTH);
-                       count = (int) (zone->elem_size / sizeof(uintptr_t));
-                       if (count >= numsaved) count = numsaved - 1;
-                       for (idx = 0; idx < count; idx++) ((uintptr_t *)addr)[count - 1 - idx] = zbt[idx + 1];
+                       if (numsaved == 0) {
+                               numsaved = backtrace(zbt, MAX_ZTRACE_DEPTH, NULL);
+                       }
+                       count = (unsigned int)(zone->elem_size / sizeof(uintptr_t));
+                       if (count >= numsaved) {
+                               count = numsaved - 1;
+                       }
+                       for (idx = 0; idx < count; idx++) {
+                               ((uintptr_t *)addr)[count - 1 - idx] = zbt[idx + 1];
+                       }
                }
 #endif /* DEBUG || DEVELOPMENT */
        }
 
        TRACE_MACHLEAKS(ZALLOC_CODE, ZALLOC_CODE_2, zone->elem_size, addr);
 
+
 #if KASAN_ZALLOC
-       /* Fixup the return address to skip the redzone */
-       if (zone->kasan_redzone) {
-               addr = kasan_alloc(addr, zone->elem_size,
-                               zone->elem_size - 2 * zone->kasan_redzone, zone->kasan_redzone);
-       }
+       addr = kasan_fixup_allocated_element_address(zone, addr);
 #endif
 
-       return((void *)addr);
+       DTRACE_VM2(zalloc, zone_t, zone, void*, addr);
+
+       return (void *)addr;
 }
 
 void *
 zalloc(zone_t zone)
 {
-       return (zalloc_internal(zone, TRUE, FALSE, 0, VM_KERN_MEMORY_NONE));
+       return zalloc_internal(zone, TRUE, FALSE, 0, VM_KERN_MEMORY_NONE);
 }
 
 void *
 zalloc_noblock(zone_t zone)
 {
-       return (zalloc_internal(zone, FALSE, FALSE, 0, VM_KERN_MEMORY_NONE));
+       return zalloc_internal(zone, FALSE, FALSE, 0, VM_KERN_MEMORY_NONE);
 }
 
 void *
 zalloc_nopagewait(zone_t zone)
 {
-       return (zalloc_internal(zone, TRUE, TRUE, 0, VM_KERN_MEMORY_NONE));
+       return zalloc_internal(zone, TRUE, TRUE, 0, VM_KERN_MEMORY_NONE);
 }
 
 void *
 zalloc_canblock_tag(zone_t zone, boolean_t canblock, vm_size_t reqsize, vm_tag_t tag)
 {
-       return (zalloc_internal(zone, canblock, FALSE, reqsize, tag));
+       return zalloc_internal(zone, canblock, FALSE, reqsize, tag);
 }
 
 void *
 zalloc_canblock(zone_t zone, boolean_t canblock)
 {
-    return (zalloc_internal(zone, canblock, FALSE, 0, VM_KERN_MEMORY_NONE));
+       return zalloc_internal(zone, canblock, FALSE, 0, VM_KERN_MEMORY_NONE);
+}
+
+void *
+zalloc_attempt(zone_t zone)
+{
+       boolean_t check_poison = FALSE;
+       vm_offset_t addr = try_alloc_from_zone(zone, VM_KERN_MEMORY_NONE, &check_poison);
+       zalloc_poison_element(check_poison, zone, addr);
+       return (void *)addr;
+}
+
+void
+zfree_direct(zone_t zone, vm_offset_t elem)
+{
+       boolean_t       poison = zfree_poison_element(zone, elem);
+       free_to_zone(zone, elem, poison);
 }
 
 
@@ -3382,8 +3724,8 @@ zalloc_async(
        unsigned int max_zones, i;
        void *elt = NULL;
        boolean_t pending = FALSE;
-       
-       simple_lock(&all_zones_lock);
+
+       simple_lock(&all_zones_lock, &zone_locks_grp);
        max_zones = num_zones;
        simple_unlock(&all_zones_lock);
        for (i = 0; i < max_zones; i++) {
@@ -3415,87 +3757,113 @@ zalloc_async(
  */
 void *
 zget(
-       zone_t  zone)
+       zone_t  zone)
 {
-    return zalloc_internal(zone, FALSE, TRUE, 0, VM_KERN_MEMORY_NONE);
+       return zalloc_internal(zone, FALSE, TRUE, 0, VM_KERN_MEMORY_NONE);
 }
 
 /* Keep this FALSE by default.  Large memory machine run orders of magnitude
-   slower in debug mode when true.  Use debugger to enable if needed */
*  slower in debug mode when true.  Use debugger to enable if needed */
 /* static */ boolean_t zone_check = FALSE;
 
-static void zone_check_freelist(zone_t zone, vm_offset_t elem)
+static void
+zone_check_freelist(zone_t zone, vm_offset_t elem)
 {
        struct zone_free_element *this;
        struct zone_page_metadata *thispage;
 
        if (zone->allows_foreign) {
                for (thispage = (struct zone_page_metadata *)queue_first(&zone->pages.any_free_foreign);
-                        !queue_end(&zone->pages.any_free_foreign, &(thispage->pages));
-                        thispage = (struct zone_page_metadata *)queue_next(&(thispage->pages))) {
+                   !queue_end(&zone->pages.any_free_foreign, &(thispage->pages));
+                   thispage = (struct zone_page_metadata *)queue_next(&(thispage->pages))) {
                        for (this = page_metadata_get_freelist(thispage);
-                                this != NULL;
-                                this = this->next) {
-                               if (!is_sane_zone_element(zone, (vm_address_t)this) || (vm_address_t)this == elem)
+                           this != NULL;
+                           this = this->next) {
+                               if (!is_sane_zone_element(zone, (vm_address_t)this) || (vm_address_t)this == elem) {
                                        panic("zone_check_freelist");
+                               }
                        }
                }
        }
        for (thispage = (struct zone_page_metadata *)queue_first(&zone->pages.all_free);
-               !queue_end(&zone->pages.all_free, &(thispage->pages));
-               thispage = (struct zone_page_metadata *)queue_next(&(thispage->pages))) {
+           !queue_end(&zone->pages.all_free, &(thispage->pages));
+           thispage = (struct zone_page_metadata *)queue_next(&(thispage->pages))) {
                for (this = page_metadata_get_freelist(thispage);
-                       this != NULL;
-                       this = this->next) {
-                       if (!is_sane_zone_element(zone, (vm_address_t)this) || (vm_address_t)this == elem)
+                   this != NULL;
+                   this = this->next) {
+                       if (!is_sane_zone_element(zone, (vm_address_t)this) || (vm_address_t)this == elem) {
                                panic("zone_check_freelist");
+                       }
                }
        }
        for (thispage = (struct zone_page_metadata *)queue_first(&zone->pages.intermediate);
-               !queue_end(&zone->pages.intermediate, &(thispage->pages));
-               thispage = (struct zone_page_metadata *)queue_next(&(thispage->pages))) {
+           !queue_end(&zone->pages.intermediate, &(thispage->pages));
+           thispage = (struct zone_page_metadata *)queue_next(&(thispage->pages))) {
                for (this = page_metadata_get_freelist(thispage);
-                       this != NULL;
-                       this = this->next) {
-                       if (!is_sane_zone_element(zone, (vm_address_t)this) || (vm_address_t)this == elem)
+                   this != NULL;
+                   this = this->next) {
+                       if (!is_sane_zone_element(zone, (vm_address_t)this) || (vm_address_t)this == elem) {
                                panic("zone_check_freelist");
+                       }
                }
        }
 }
 
+boolean_t
+zfree_poison_element(zone_t zone, vm_offset_t elem)
+{
+       boolean_t       poison = FALSE;
+       if (zp_factor != 0 || zp_tiny_zone_limit != 0) {
+               /*
+                * Poison the memory before it ends up on the freelist to catch
+                * use-after-free and use of uninitialized memory
+                *
+                * Always poison tiny zones' elements (limit is 0 if -no-zp is set)
+                * Also poison larger elements periodically
+                */
+
+               vm_offset_t     inner_size = zone->elem_size;
+
+               uint32_t sample_factor = zp_factor + (((uint32_t)inner_size) >> zp_scale);
+
+               if (inner_size <= zp_tiny_zone_limit) {
+                       poison = TRUE;
+               } else if (zp_factor != 0 && sample_counter(&zone->zp_count, sample_factor) == TRUE) {
+                       poison = TRUE;
+               }
+
+               if (__improbable(poison)) {
+                       /* memset_pattern{4|8} could help make this faster: <rdar://problem/4662004> */
+                       /* Poison everything but primary and backup */
+                       vm_offset_t *element_cursor  = ((vm_offset_t *) elem) + 1;
+                       vm_offset_t *backup   = get_backup_ptr(inner_size, (vm_offset_t *)elem);
+
+                       for (; element_cursor < backup; element_cursor++) {
+                               *element_cursor = ZP_POISON;
+                       }
+               }
+       }
+       return poison;
+}
 void
-zfree(
-       zone_t  zone,
-       void            *addr)
+(zfree)(
+       zone_t  zone,
+       void            *addr)
 {
-       vm_offset_t     elem = (vm_offset_t) addr;
-       uintptr_t       zbt[MAX_ZTRACE_DEPTH];                  /* only used if zone logging is enabled via boot-args */
-       int             numsaved = 0;
-       boolean_t       gzfreed = FALSE;
+       vm_offset_t     elem = (vm_offset_t) addr;
+       uintptr_t       zbt[MAX_ZTRACE_DEPTH];                  /* only used if zone logging is enabled via boot-args */
+       unsigned int            numsaved = 0;
+       boolean_t       gzfreed = FALSE;
        boolean_t       poison = FALSE;
 #if VM_MAX_TAG_ZONES
-    vm_tag_t tag;
+       vm_tag_t tag;
 #endif /* VM_MAX_TAG_ZONES */
 
        assert(zone != ZONE_NULL);
-
+       DTRACE_VM2(zfree, zone_t, zone, void*, addr);
 #if KASAN_ZALLOC
-       /*
-        * Resize back to the real allocation size and hand off to the KASan
-        * quarantine. `addr` may then point to a different allocation.
-        */
-       vm_size_t usersz = zone->elem_size - 2 * zone->kasan_redzone;
-       vm_size_t sz = usersz;
-       if (addr && zone->kasan_redzone) {
-               kasan_check_free((vm_address_t)addr, usersz, KASAN_HEAP_ZALLOC);
-               addr = (void *)kasan_dealloc((vm_address_t)addr, &sz);
-               assert(sz == zone->elem_size);
-       }
-       if (addr && zone->kasan_quarantine) {
-               kasan_free(&addr, &sz, KASAN_HEAP_ZALLOC, &zone, usersz, true);
-               if (!addr) {
-                       return;
-               }
+       if (kasan_quarantine_freed_element(&zone, &addr)) {
+               return;
        }
        elem = (vm_offset_t)addr;
 #endif
@@ -3504,16 +3872,18 @@ zfree(
         * If zone logging is turned on and this is the zone we're tracking, grab a backtrace.
         */
 
-       if (__improbable(DO_LOGGING(zone) && corruption_debug_flag))
+       if (__improbable(DO_LOGGING(zone) && corruption_debug_flag)) {
                numsaved = OSBacktrace((void *)zbt, MAX_ZTRACE_DEPTH);
+       }
 
 #if MACH_ASSERT
        /* Basic sanity checks */
-       if (zone == ZONE_NULL || elem == (vm_offset_t)0)
+       if (zone == ZONE_NULL || elem == (vm_offset_t)0) {
                panic("zfree: NULL");
+       }
 #endif
 
-#if    CONFIG_GZALLOC  
+#if     CONFIG_GZALLOC
        gzfreed = gzalloc_free(zone, addr);
 #endif
 
@@ -3527,38 +3897,12 @@ zfree(
        TRACE_MACHLEAKS(ZFREE_CODE, ZFREE_CODE_2, zone->elem_size, (uintptr_t)addr);
 
        if (__improbable(!gzfreed && zone->collectable && !zone->allows_foreign &&
-               !from_zone_map(elem, zone->elem_size))) {
+           !from_zone_map(elem, zone->elem_size))) {
                panic("zfree: non-allocated memory in collectable zone!");
        }
 
-       if ((zp_factor != 0 || zp_tiny_zone_limit != 0) && !gzfreed) {
-               /*
-                * Poison the memory before it ends up on the freelist to catch
-                * use-after-free and use of uninitialized memory
-                *
-                * Always poison tiny zones' elements (limit is 0 if -no-zp is set)
-                * Also poison larger elements periodically
-                */
-
-               vm_offset_t     inner_size = zone->elem_size;
-
-               uint32_t sample_factor = zp_factor + (((uint32_t)inner_size) >> zp_scale);
-
-               if (inner_size <= zp_tiny_zone_limit)
-                       poison = TRUE;
-               else if (zp_factor != 0 && sample_counter(&zone->zp_count, sample_factor) == TRUE)
-                       poison = TRUE;
-
-               if (__improbable(poison)) {
-
-                       /* memset_pattern{4|8} could help make this faster: <rdar://problem/4662004> */
-                       /* Poison everything but primary and backup */
-                       vm_offset_t *element_cursor  = ((vm_offset_t *) elem) + 1;
-                       vm_offset_t *backup   = get_backup_ptr(inner_size, (vm_offset_t *)elem);
-
-                       for ( ; element_cursor < backup; element_cursor++)
-                               *element_cursor = ZP_POISON;
-               }
+       if (!gzfreed) {
+               poison = zfree_poison_element(zone, elem);
        }
 
        /*
@@ -3584,6 +3928,14 @@ zfree(
                }
        }
 
+#if CONFIG_ZCACHE
+       if (zone_caching_enabled(zone)) {
+               int __assert_only ret = zcache_free_to_cpu_cache(zone, addr);
+               assert(ret != FALSE);
+               return;
+       }
+#endif /* CONFIG_ZCACHE */
+
        lock_zone(zone);
        assert(zone->zone_valid);
 
@@ -3593,31 +3945,29 @@ zfree(
 
        if (__probable(!gzfreed)) {
 #if VM_MAX_TAG_ZONES
-           if (__improbable(zone->tags)) {
+               if (__improbable(zone->tags)) {
                        tag = (ZTAG(zone, elem)[0] >> 1);
                        // set the tag with b0 clear so the block remains inuse
                        ZTAG(zone, elem)[0] = 0xFFFE;
-           }
+               }
 #endif /* VM_MAX_TAG_ZONES */
                free_to_zone(zone, elem, poison);
        }
 
-#if MACH_ASSERT
-       if (zone->count < 0)
+       if (__improbable(zone->count < 0)) {
                panic("zfree: zone count underflow in zone %s while freeing element %p, possible cause: double frees or freeing memory that did not come from this zone",
-               zone->zone_name, addr);
-#endif
-       
+                   zone->zone_name, addr);
+       }
 
 #if CONFIG_ZLEAKS
        /*
-        * Zone leak detection: un-track the allocation 
+        * Zone leak detection: un-track the allocation
         */
        if (zone->zleak_on) {
                zleak_free(elem, zone->elem_size);
        }
 #endif /* CONFIG_ZLEAKS */
-       
+
 #if VM_MAX_TAG_ZONES
        if (__improbable(zone->tags) && __probable(!gzfreed)) {
                vm_tag_update_zone_size(tag, zone->tag_zone_index, -((int64_t)zone->elem_size), 0);
@@ -3632,71 +3982,94 @@ zfree(
  */
 void
 zone_change(
-       zone_t          zone,
-       unsigned int    item,
-       boolean_t       value)
+       zone_t          zone,
+       unsigned int    item,
+       boolean_t       value)
 {
        assert( zone != ZONE_NULL );
        assert( value == TRUE || value == FALSE );
 
-       switch(item){
-               case Z_NOENCRYPT:
-                       zone->noencrypt = value;
-                       break;
-               case Z_EXHAUST:
-                       zone->exhaustible = value;
-                       break;
-               case Z_COLLECT:
-                       zone->collectable = value;
-                       break;
-               case Z_EXPAND:
-                       zone->expandable = value;
-                       break;
-               case Z_FOREIGN:
-                       zone->allows_foreign = value;
-                       break;
-               case Z_CALLERACCT:
-                       zone->caller_acct = value;
-                       break;
-               case Z_NOCALLOUT:
-                       zone->no_callout = value;
-                       break;
-               case Z_TAGS_ENABLED:
+       switch (item) {
+       case Z_NOENCRYPT:
+               zone->noencrypt = value;
+               break;
+       case Z_EXHAUST:
+               zone->exhaustible = value;
+               break;
+       case Z_COLLECT:
+               zone->collectable = value;
+               break;
+       case Z_EXPAND:
+               zone->expandable = value;
+               break;
+       case Z_FOREIGN:
+               zone->allows_foreign = value;
+               break;
+       case Z_CALLERACCT:
+               zone->caller_acct = value;
+               break;
+       case Z_NOCALLOUT:
+               zone->no_callout = value;
+               break;
+       case Z_TAGS_ENABLED:
 #if VM_MAX_TAG_ZONES
-                       {
-                               static int tag_zone_index;
-                               zone->tags = TRUE;
-                               zone->tags_inline = (((page_size + zone->elem_size - 1) / zone->elem_size) <= (sizeof(uint32_t) / sizeof(uint16_t)));
-                               zone->tag_zone_index = OSAddAtomic(1, &tag_zone_index);
-                       }
+               {
+                       static int tag_zone_index;
+                       zone->tags = TRUE;
+                       zone->tags_inline = (((page_size + zone->elem_size - 1) / zone->elem_size) <= (sizeof(uint32_t) / sizeof(uint16_t)));
+                       zone->tag_zone_index = OSAddAtomic(1, &tag_zone_index);
+               }
 #endif /* VM_MAX_TAG_ZONES */
-                       break;
-               case Z_GZALLOC_EXEMPT:
-                       zone->gzalloc_exempt = value;
-#if    CONFIG_GZALLOC
-                       gzalloc_reconfigure(zone);
+               break;
+       case Z_GZALLOC_EXEMPT:
+               zone->gzalloc_exempt = value;
+#if     CONFIG_GZALLOC
+               gzalloc_reconfigure(zone);
 #endif
-                       break;
-               case Z_ALIGNMENT_REQUIRED:
-                       zone->alignment_required = value;
+               break;
+       case Z_ALIGNMENT_REQUIRED:
+               zone->alignment_required = value;
 #if KASAN_ZALLOC
-                       if (zone->kasan_redzone == KASAN_GUARD_SIZE) {
-                               /* Don't disturb alignment with the redzone for zones with
-                                * specific alignment requirements. */
-                               zone->elem_size -= zone->kasan_redzone * 2;
-                               zone->kasan_redzone = 0;
+               if (zone->kasan_redzone == KASAN_GUARD_SIZE) {
+                       /* Don't disturb alignment with the redzone for zones with
+                        * specific alignment requirements. */
+                       zone->elem_size -= zone->kasan_redzone * 2;
+                       zone->kasan_redzone = 0;
+               }
+#endif
+#if     CONFIG_GZALLOC
+               gzalloc_reconfigure(zone);
+#endif
+               break;
+       case Z_KASAN_QUARANTINE:
+               zone->kasan_quarantine = value;
+               break;
+       case Z_CACHING_ENABLED:
+#if     CONFIG_ZCACHE
+               if (value == TRUE) {
+#if     CONFIG_GZALLOC
+                       /*
+                        * Per cpu zone caching should be
+                        * disabled if gzalloc is enabled.
+                        */
+                       if (gzalloc_enabled()) {
+                               break;
                        }
 #endif
-#if    CONFIG_GZALLOC
-                       gzalloc_reconfigure(zone);
+                       if (zcache_ready()) {
+                               zcache_init(zone);
+                       } else {
+                               zone->cpu_cache_enable_when_ready = TRUE;
+                       }
+               }
 #endif
-                       break;
-               case Z_KASAN_QUARANTINE:
-                       zone->kasan_quarantine = value;
-                       break;
-               default:
-                       panic("Zone_change: Wrong Item Type!");
-                       /* break; */
+               break;
+       case Z_CLEARMEMORY:
+               zone->clear_memory = value;
+               break;
+       default:
+               panic("Zone_change: Wrong Item Type!");
+               /* break; */
        }
 }
 
@@ -3718,72 +4091,84 @@ zone_free_count(zone_t zone)
 
        assert(free_count >= 0);
 
-       return(free_count);
+       return free_count;
 }
 
-/* Drops the elements in the free queue of a zone. Called by zone_gc() on each zone, and when a zone is zdestroy'ed. */
+/*
+ * Drops (i.e. frees) the elements in the all free pages queue of a zone.
+ * Called by zone_gc() on each zone and when a zone is zdestroy()ed.
+ */
 void
 drop_free_elements(zone_t z)
 {
-       vm_size_t                                       elt_size, size_freed;
-       int                                                     total_freed_pages = 0;
-       uint64_t                                        old_all_free_count;
-       struct zone_page_metadata       *page_meta;
-       queue_head_t                            page_meta_head;
+       vm_size_t                 elt_size;
+       unsigned int              total_freed_pages = 0;
+       struct zone_page_metadata *page_meta;
+       vm_address_t              free_page_address;
+       vm_size_t                 size_to_free;
 
        lock_zone(z);
-       if (queue_empty(&z->pages.all_free)) {
-               unlock_zone(z);
-               return;
-       }
 
-       /*
-        * Snatch all of the free elements away from the zone.
-        */
        elt_size = z->elem_size;
-       old_all_free_count = z->count_all_free_pages;
-       queue_new_head(&z->pages.all_free, &page_meta_head, struct zone_page_metadata *, pages);
-       queue_init(&z->pages.all_free);
-       z->count_all_free_pages = 0;
-       unlock_zone(z);
 
-       /* Iterate through all elements to find out size and count of elements we snatched */
-       size_freed = 0;
-       queue_iterate(&page_meta_head, page_meta, struct zone_page_metadata *, pages) {
+       while (!queue_empty(&z->pages.all_free)) {
+               page_meta = (struct zone_page_metadata *)queue_first(&z->pages.all_free);
                assert(from_zone_map((vm_address_t)page_meta, sizeof(*page_meta))); /* foreign elements should be in any_free_foreign */
-               size_freed += elt_size * page_meta->free_count;
-       }
+               /*
+                * Don't drain zones with async refill to below the refill threshold,
+                * as they need some reserve to function properly.
+                */
+               if (!z->zone_destruction &&
+                   z->async_prio_refill && z->zone_replenish_thread &&
+                   (vm_size_t)(page_meta->free_count - z->countfree) < z->prio_refill_watermark) {
+                       break;
+               }
 
-       /* Update the zone size and free element count */
-       lock_zone(z);
-       z->cur_size -= size_freed;
-       z->countfree -= size_freed/elt_size;
-       unlock_zone(z);
+               (void)dequeue_head(&z->pages.all_free);
+
+               assert(z->countfree >= page_meta->free_count);
+               z->countfree -= page_meta->free_count;
+
+               assert(z->count_all_free_pages >= page_meta->page_count);
+               z->count_all_free_pages -= page_meta->page_count;
+
+               assert(z->cur_size >= page_meta->free_count * elt_size);
+               z->cur_size -= page_meta->free_count * elt_size;
+
+               ZONE_PAGE_COUNT_DECR(z, page_meta->page_count);
+               unlock_zone(z);
 
-       while ((page_meta = (struct zone_page_metadata *)dequeue_head(&page_meta_head)) != NULL) {
-               vm_address_t        free_page_address;
                /* Free the pages for metadata and account for them */
                free_page_address = get_zone_page(page_meta);
-               ZONE_PAGE_COUNT_DECR(z, page_meta->page_count);
                total_freed_pages += page_meta->page_count;
-               old_all_free_count -= page_meta->page_count;
+               size_to_free = page_meta->page_count * PAGE_SIZE;
 #if KASAN_ZALLOC
-               kasan_poison_range(free_page_address, page_meta->page_count * PAGE_SIZE, ASAN_VALID);
+               kasan_poison_range(free_page_address, size_to_free, ASAN_VALID);
 #endif
 #if VM_MAX_TAG_ZONES
-        if (z->tags) ztMemoryRemove(z, free_page_address, (page_meta->page_count * PAGE_SIZE));
+               if (z->tags) {
+                       ztMemoryRemove(z, free_page_address, size_to_free);
+               }
 #endif /* VM_MAX_TAG_ZONES */
-               kmem_free(zone_map, free_page_address, (page_meta->page_count * PAGE_SIZE));
+               kmem_free(zone_map, free_page_address, size_to_free);
                if (current_thread()->options & TH_OPT_ZONE_GC) {
                        thread_yield_to_preemption();
                }
+               lock_zone(z);
+       }
+       if (z->zone_destruction) {
+               assert(queue_empty(&z->pages.all_free));
+               assert(z->count_all_free_pages == 0);
        }
+       unlock_zone(z);
 
-       /* We freed all the pages from the all_free list for this zone */
-       assert(old_all_free_count == 0);
 
-       if (zalloc_debug & ZALLOC_DEBUG_ZONEGC)
-               kprintf("zone_gc() of zone %s freed %lu elements, %d pages\n", z->zone_name, (unsigned long)size_freed/elt_size, total_freed_pages);
+#if DEBUG || DEVELOPMENT
+       if (zalloc_debug & ZALLOC_DEBUG_ZONEGC) {
+               kprintf("zone_gc() of zone %s freed %lu elements, %d pages\n", z->zone_name,
+                   (unsigned long)((total_freed_pages * PAGE_SIZE) / elt_size), total_freed_pages);
+       }
+#endif /* DEBUG || DEVELOPMENT */
 }
 
 /*     Zone garbage collection
@@ -3798,9 +4183,9 @@ drop_free_elements(zone_t z)
 void
 zone_gc(boolean_t consider_jetsams)
 {
-       unsigned int    max_zones;
-       zone_t                  z;
-       unsigned int    i;
+       unsigned int    max_zones;
+       zone_t                  z;
+       unsigned int    i;
 
        if (consider_jetsams) {
                kill_process_in_largest_zone();
@@ -3815,12 +4200,15 @@ zone_gc(boolean_t consider_jetsams)
 
        current_thread()->options |= TH_OPT_ZONE_GC;
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
        max_zones = num_zones;
        simple_unlock(&all_zones_lock);
 
-       if (zalloc_debug & ZALLOC_DEBUG_ZONEGC)
+#if DEBUG || DEVELOPMENT
+       if (zalloc_debug & ZALLOC_DEBUG_ZONEGC) {
                kprintf("zone_gc() starting...\n");
+       }
+#endif /* DEBUG || DEVELOPMENT */
 
        for (i = 0; i < max_zones; i++) {
                z = &(zone_array[i]);
@@ -3829,11 +4217,15 @@ zone_gc(boolean_t consider_jetsams)
                if (!z->collectable) {
                        continue;
                }
-               
+#if CONFIG_ZCACHE
+               if (zone_caching_enabled(z)) {
+                       zcache_drain_depot(z);
+               }
+#endif /* CONFIG_ZCACHE */
                if (queue_empty(&z->pages.all_free)) {
                        continue;
                }
-               
+
                drop_free_elements(z);
        }
 
@@ -3864,16 +4256,93 @@ consider_zone_gc(boolean_t consider_jetsams)
                kmapoff_kaddr = 0;
        }
 
-       if (zone_gc_allowed)
+       if (zone_gc_allowed) {
                zone_gc(consider_jetsams);
+       }
+}
+
+/*
+ * Creates a vm_map_copy_t to return to the caller of mach_* MIG calls
+ * requesting zone information.
+ * Frees unused pages towards the end of the region, and zero'es out unused
+ * space on the last page.
+ */
+vm_map_copy_t
+create_vm_map_copy(
+       vm_offset_t             start_addr,
+       vm_size_t               total_size,
+       vm_size_t               used_size)
+{
+       kern_return_t   kr;
+       vm_offset_t             end_addr;
+       vm_size_t               free_size;
+       vm_map_copy_t   copy;
+
+       if (used_size != total_size) {
+               end_addr = start_addr + used_size;
+               free_size = total_size - (round_page(end_addr) - start_addr);
+
+               if (free_size >= PAGE_SIZE) {
+                       kmem_free(ipc_kernel_map,
+                           round_page(end_addr), free_size);
+               }
+               bzero((char *) end_addr, round_page(end_addr) - end_addr);
+       }
+
+       kr = vm_map_copyin(ipc_kernel_map, (vm_map_address_t)start_addr,
+           (vm_map_size_t)used_size, TRUE, &copy);
+       assert(kr == KERN_SUCCESS);
+
+       return copy;
+}
+
+boolean_t
+get_zone_info(
+       zone_t                          z,
+       mach_zone_name_t        *zn,
+       mach_zone_info_t        *zi)
+{
+       struct zone zcopy;
+
+       assert(z != ZONE_NULL);
+       lock_zone(z);
+       if (!z->zone_valid) {
+               unlock_zone(z);
+               return FALSE;
+       }
+       zcopy = *z;
+       unlock_zone(z);
+
+       if (zn != NULL) {
+               /* assuming here the name data is static */
+               (void) __nosan_strlcpy(zn->mzn_name, zcopy.zone_name,
+                   strlen(zcopy.zone_name) + 1);
+       }
+
+       if (zi != NULL) {
+               zi->mzi_count = (uint64_t)zcopy.count;
+               zi->mzi_cur_size = ptoa_64(zcopy.page_count);
+               zi->mzi_max_size = (uint64_t)zcopy.max_size;
+               zi->mzi_elem_size = (uint64_t)zcopy.elem_size;
+               zi->mzi_alloc_size = (uint64_t)zcopy.alloc_size;
+               zi->mzi_sum_size = zcopy.sum_count * zcopy.elem_size;
+               zi->mzi_exhaustible = (uint64_t)zcopy.exhaustible;
+               zi->mzi_collectable = 0;
+               if (zcopy.collectable) {
+                       SET_MZI_COLLECTABLE_BYTES(zi->mzi_collectable, ((uint64_t)zcopy.count_all_free_pages * PAGE_SIZE));
+                       SET_MZI_COLLECTABLE_FLAG(zi->mzi_collectable, TRUE);
+               }
+       }
+
+       return TRUE;
 }
 
 kern_return_t
 task_zone_info(
-       __unused task_t                                 task,
-       __unused mach_zone_name_array_t *namesp,
+       __unused task_t                                 task,
+       __unused mach_zone_name_array_t *namesp,
        __unused mach_msg_type_number_t *namesCntp,
-       __unused task_zone_info_array_t *infop,
+       __unused task_zone_info_array_t *infop,
        __unused mach_msg_type_number_t *infoCntp)
 {
        return KERN_FAILURE;
@@ -3881,55 +4350,54 @@ task_zone_info(
 
 kern_return_t
 mach_zone_info(
-       host_priv_t             host,
-       mach_zone_name_array_t  *namesp,
+       host_priv_t             host,
+       mach_zone_name_array_t  *namesp,
        mach_msg_type_number_t  *namesCntp,
-       mach_zone_info_array_t  *infop,
+       mach_zone_info_array_t  *infop,
        mach_msg_type_number_t  *infoCntp)
 {
-       return (mach_memory_info(host, namesp, namesCntp, infop, infoCntp, NULL, NULL));
+       return mach_memory_info(host, namesp, namesCntp, infop, infoCntp, NULL, NULL);
 }
 
 
 kern_return_t
 mach_memory_info(
-       host_priv_t             host,
-       mach_zone_name_array_t  *namesp,
+       host_priv_t             host,
+       mach_zone_name_array_t  *namesp,
        mach_msg_type_number_t  *namesCntp,
-       mach_zone_info_array_t  *infop,
+       mach_zone_info_array_t  *infop,
        mach_msg_type_number_t  *infoCntp,
        mach_memory_info_array_t *memoryInfop,
        mach_msg_type_number_t   *memoryInfoCntp)
 {
-       mach_zone_name_t        *names;
-       vm_offset_t             names_addr;
-       vm_size_t               names_size;
-
-       mach_zone_info_t        *info;
-       vm_offset_t             info_addr;
-       vm_size_t               info_size;
-
-       mach_memory_info_t      *memory_info;
-       vm_offset_t             memory_info_addr;
-       vm_size_t               memory_info_size;
-       vm_size_t               memory_info_vmsize;
-        unsigned int           num_info;
-
-       unsigned int            max_zones, used_zones, i;
-       zone_t                  z;
-       mach_zone_name_t        *zn;
-       mach_zone_info_t        *zi;
-       kern_return_t           kr;
-       
-       vm_size_t               used;
-       vm_map_copy_t           copy;
-       uint64_t                zones_collectable_bytes = 0;
-
-       if (host == HOST_NULL)
+       mach_zone_name_t        *names;
+       vm_offset_t             names_addr;
+       vm_size_t               names_size;
+
+       mach_zone_info_t        *info;
+       vm_offset_t             info_addr;
+       vm_size_t               info_size;
+
+       mach_memory_info_t      *memory_info;
+       vm_offset_t             memory_info_addr;
+       vm_size_t               memory_info_size;
+       vm_size_t               memory_info_vmsize;
+       unsigned int            num_info;
+
+       unsigned int            max_zones, used_zones, i;
+       mach_zone_name_t        *zn;
+       mach_zone_info_t        *zi;
+       kern_return_t           kr;
+
+       uint64_t                zones_collectable_bytes = 0;
+
+       if (host == HOST_NULL) {
                return KERN_INVALID_HOST;
+       }
 #if CONFIG_DEBUGGER_FOR_ZONE_INFO
-       if (!PE_i_can_has_debugger(NULL))
+       if (!PE_i_can_has_debugger(NULL)) {
                return KERN_INVALID_HOST;
+       }
 #endif
 
        /*
@@ -3937,23 +4405,24 @@ mach_memory_info(
         *      We won't pick up any zones that are allocated later.
         */
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
        max_zones = (unsigned int)(num_zones);
        simple_unlock(&all_zones_lock);
 
        names_size = round_page(max_zones * sizeof *names);
        kr = kmem_alloc_pageable(ipc_kernel_map,
-                                &names_addr, names_size, VM_KERN_MEMORY_IPC);
-       if (kr != KERN_SUCCESS)
+           &names_addr, names_size, VM_KERN_MEMORY_IPC);
+       if (kr != KERN_SUCCESS) {
                return kr;
+       }
        names = (mach_zone_name_t *) names_addr;
 
        info_size = round_page(max_zones * sizeof *info);
        kr = kmem_alloc_pageable(ipc_kernel_map,
-                                &info_addr, info_size, VM_KERN_MEMORY_IPC);
+           &info_addr, info_size, VM_KERN_MEMORY_IPC);
        if (kr != KERN_SUCCESS) {
                kmem_free(ipc_kernel_map,
-                         names_addr, names_size);
+                   names_addr, names_size);
                return kr;
        }
        info = (mach_zone_info_t *) info_addr;
@@ -3963,80 +4432,37 @@ mach_memory_info(
 
        used_zones = max_zones;
        for (i = 0; i < max_zones; i++) {
-               struct zone zcopy;
-               z = &(zone_array[i]);
-               assert(z != ZONE_NULL);
-
-               lock_zone(z);
-               if (!z->zone_valid) {
-                       unlock_zone(z);
+               if (!get_zone_info(&(zone_array[i]), zn, zi)) {
                        used_zones--;
                        continue;
                }
-               zcopy = *z;
-               unlock_zone(z);
-
-               /* assuming here the name data is static */
-               (void) __nosan_strncpy(zn->mzn_name, zcopy.zone_name,
-                              sizeof zn->mzn_name);
-               zn->mzn_name[sizeof zn->mzn_name - 1] = '\0';
-
-               zi->mzi_count = (uint64_t)zcopy.count;
-               zi->mzi_cur_size = ptoa_64(zcopy.page_count);
-               zi->mzi_max_size = (uint64_t)zcopy.max_size;
-               zi->mzi_elem_size = (uint64_t)zcopy.elem_size;
-               zi->mzi_alloc_size = (uint64_t)zcopy.alloc_size;
-               zi->mzi_sum_size = zcopy.sum_count * zcopy.elem_size;
-               zi->mzi_exhaustible = (uint64_t)zcopy.exhaustible;
-               zi->mzi_collectable = (uint64_t)zcopy.collectable;
-               zones_collectable_bytes += ((uint64_t)zcopy.count_all_free_pages * PAGE_SIZE);
+               zones_collectable_bytes += GET_MZI_COLLECTABLE_BYTES(zi->mzi_collectable);
                zn++;
                zi++;
        }
 
-       used = used_zones * sizeof *names;
-       if (used != names_size)
-               bzero((char *) (names_addr + used), names_size - used);
-
-       kr = vm_map_copyin(ipc_kernel_map, (vm_map_address_t)names_addr,
-                          (vm_map_size_t)used, TRUE, &copy);
-       assert(kr == KERN_SUCCESS);
-
-       *namesp = (mach_zone_name_t *) copy;
+       *namesp = (mach_zone_name_t *) create_vm_map_copy(names_addr, names_size, used_zones * sizeof *names);
        *namesCntp = used_zones;
 
-       used = used_zones * sizeof *info;
-
-       if (used != info_size)
-               bzero((char *) (info_addr + used), info_size - used);
-
-       kr = vm_map_copyin(ipc_kernel_map, (vm_map_address_t)info_addr,
-                          (vm_map_size_t)used, TRUE, &copy);
-       assert(kr == KERN_SUCCESS);
-
-       *infop = (mach_zone_info_t *) copy;
+       *infop = (mach_zone_info_t *) create_vm_map_copy(info_addr, info_size, used_zones * sizeof *info);
        *infoCntp = used_zones;
-       
+
        num_info = 0;
        memory_info_addr = 0;
 
-       if (memoryInfop && memoryInfoCntp)
-       {
+       if (memoryInfop && memoryInfoCntp) {
+               vm_map_copy_t           copy;
                num_info = vm_page_diagnose_estimate();
                memory_info_size = num_info * sizeof(*memory_info);
                memory_info_vmsize = round_page(memory_info_size);
                kr = kmem_alloc_pageable(ipc_kernel_map,
-                                        &memory_info_addr, memory_info_vmsize, VM_KERN_MEMORY_IPC);
+                   &memory_info_addr, memory_info_vmsize, VM_KERN_MEMORY_IPC);
                if (kr != KERN_SUCCESS) {
-                       kmem_free(ipc_kernel_map,
-                                 names_addr, names_size);
-                       kmem_free(ipc_kernel_map,
-                                 info_addr, info_size);
                        return kr;
                }
 
                kr = vm_map_wire_kernel(ipc_kernel_map, memory_info_addr, memory_info_addr + memory_info_vmsize,
-                                    VM_PROT_READ|VM_PROT_WRITE, VM_KERN_MEMORY_IPC, FALSE);
+                   VM_PROT_READ | VM_PROT_WRITE, VM_KERN_MEMORY_IPC, FALSE);
                assert(kr == KERN_SUCCESS);
 
                memory_info = (mach_memory_info_t *) memory_info_addr;
@@ -4044,9 +4470,9 @@ mach_memory_info(
 
                kr = vm_map_unwire(ipc_kernel_map, memory_info_addr, memory_info_addr + memory_info_vmsize, FALSE);
                assert(kr == KERN_SUCCESS);
-       
+
                kr = vm_map_copyin(ipc_kernel_map, (vm_map_address_t)memory_info_addr,
-                                  (vm_map_size_t)memory_info_size, TRUE, &copy);
+                   (vm_map_size_t)memory_info_size, TRUE, &copy);
                assert(kr == KERN_SUCCESS);
 
                *memoryInfop = (mach_memory_info_t *) copy;
@@ -4056,118 +4482,339 @@ mach_memory_info(
        return KERN_SUCCESS;
 }
 
+kern_return_t
+mach_zone_info_for_zone(
+       host_priv_t                     host,
+       mach_zone_name_t        name,
+       mach_zone_info_t        *infop)
+{
+       unsigned int max_zones, i;
+       zone_t zone_ptr;
+
+       if (host == HOST_NULL) {
+               return KERN_INVALID_HOST;
+       }
+#if CONFIG_DEBUGGER_FOR_ZONE_INFO
+       if (!PE_i_can_has_debugger(NULL)) {
+               return KERN_INVALID_HOST;
+       }
+#endif
+
+       if (infop == NULL) {
+               return KERN_INVALID_ARGUMENT;
+       }
+
+       simple_lock(&all_zones_lock, &zone_locks_grp);
+       max_zones = (unsigned int)(num_zones);
+       simple_unlock(&all_zones_lock);
+
+       zone_ptr = ZONE_NULL;
+       for (i = 0; i < max_zones; i++) {
+               zone_t z = &(zone_array[i]);
+               assert(z != ZONE_NULL);
+
+               /* Find the requested zone by name */
+               if (track_this_zone(z->zone_name, name.mzn_name)) {
+                       zone_ptr = z;
+                       break;
+               }
+       }
+
+       /* No zones found with the requested zone name */
+       if (zone_ptr == ZONE_NULL) {
+               return KERN_INVALID_ARGUMENT;
+       }
+
+       if (get_zone_info(zone_ptr, NULL, infop)) {
+               return KERN_SUCCESS;
+       }
+       return KERN_FAILURE;
+}
+
+kern_return_t
+mach_zone_info_for_largest_zone(
+       host_priv_t                     host,
+       mach_zone_name_t        *namep,
+       mach_zone_info_t        *infop)
+{
+       if (host == HOST_NULL) {
+               return KERN_INVALID_HOST;
+       }
+#if CONFIG_DEBUGGER_FOR_ZONE_INFO
+       if (!PE_i_can_has_debugger(NULL)) {
+               return KERN_INVALID_HOST;
+       }
+#endif
+
+       if (namep == NULL || infop == NULL) {
+               return KERN_INVALID_ARGUMENT;
+       }
+
+       if (get_zone_info(zone_find_largest(), namep, infop)) {
+               return KERN_SUCCESS;
+       }
+       return KERN_FAILURE;
+}
+
 uint64_t
 get_zones_collectable_bytes(void)
 {
-       zone_t z;
        unsigned int i, max_zones;
        uint64_t zones_collectable_bytes = 0;
+       mach_zone_info_t zi;
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
        max_zones = (unsigned int)(num_zones);
        simple_unlock(&all_zones_lock);
 
        for (i = 0; i < max_zones; i++) {
-               z = &(zone_array[i]);
+               if (get_zone_info(&(zone_array[i]), NULL, &zi)) {
+                       zones_collectable_bytes += GET_MZI_COLLECTABLE_BYTES(zi.mzi_collectable);
+               }
+       }
+
+       return zones_collectable_bytes;
+}
+
+kern_return_t
+mach_zone_get_zlog_zones(
+       host_priv_t                             host,
+       mach_zone_name_array_t  *namesp,
+       mach_msg_type_number_t  *namesCntp)
+{
+#if DEBUG || DEVELOPMENT
+       unsigned int max_zones, logged_zones, i;
+       kern_return_t kr;
+       zone_t zone_ptr;
+       mach_zone_name_t *names;
+       vm_offset_t names_addr;
+       vm_size_t names_size;
+
+       if (host == HOST_NULL) {
+               return KERN_INVALID_HOST;
+       }
+
+       if (namesp == NULL || namesCntp == NULL) {
+               return KERN_INVALID_ARGUMENT;
+       }
+
+       simple_lock(&all_zones_lock, &zone_locks_grp);
+       max_zones = (unsigned int)(num_zones);
+       simple_unlock(&all_zones_lock);
+
+       names_size = round_page(max_zones * sizeof *names);
+       kr = kmem_alloc_pageable(ipc_kernel_map,
+           &names_addr, names_size, VM_KERN_MEMORY_IPC);
+       if (kr != KERN_SUCCESS) {
+               return kr;
+       }
+       names = (mach_zone_name_t *) names_addr;
+
+       zone_ptr = ZONE_NULL;
+       logged_zones = 0;
+       for (i = 0; i < max_zones; i++) {
+               zone_t z = &(zone_array[i]);
                assert(z != ZONE_NULL);
 
-               lock_zone(z);
-               zones_collectable_bytes += ((uint64_t)z->count_all_free_pages * PAGE_SIZE);
-               unlock_zone(z);
+               /* Copy out the zone name if zone logging is enabled */
+               if (z->zlog_btlog) {
+                       get_zone_info(z, &names[logged_zones], NULL);
+                       logged_zones++;
+               }
        }
 
-       return zones_collectable_bytes;
+       *namesp = (mach_zone_name_t *) create_vm_map_copy(names_addr, names_size, logged_zones * sizeof *names);
+       *namesCntp = logged_zones;
+
+       return KERN_SUCCESS;
+
+#else /* DEBUG || DEVELOPMENT */
+#pragma unused(host, namesp, namesCntp)
+       return KERN_FAILURE;
+#endif /* DEBUG || DEVELOPMENT */
+}
+
+kern_return_t
+mach_zone_get_btlog_records(
+       host_priv_t                             host,
+       mach_zone_name_t                name,
+       zone_btrecord_array_t   *recsp,
+       mach_msg_type_number_t  *recsCntp)
+{
+#if DEBUG || DEVELOPMENT
+       unsigned int max_zones, i, numrecs = 0;
+       zone_btrecord_t *recs;
+       kern_return_t kr;
+       zone_t zone_ptr;
+       vm_offset_t recs_addr;
+       vm_size_t recs_size;
+
+       if (host == HOST_NULL) {
+               return KERN_INVALID_HOST;
+       }
+
+       if (recsp == NULL || recsCntp == NULL) {
+               return KERN_INVALID_ARGUMENT;
+       }
+
+       simple_lock(&all_zones_lock, &zone_locks_grp);
+       max_zones = (unsigned int)(num_zones);
+       simple_unlock(&all_zones_lock);
+
+       zone_ptr = ZONE_NULL;
+       for (i = 0; i < max_zones; i++) {
+               zone_t z = &(zone_array[i]);
+               assert(z != ZONE_NULL);
+
+               /* Find the requested zone by name */
+               if (track_this_zone(z->zone_name, name.mzn_name)) {
+                       zone_ptr = z;
+                       break;
+               }
+       }
+
+       /* No zones found with the requested zone name */
+       if (zone_ptr == ZONE_NULL) {
+               return KERN_INVALID_ARGUMENT;
+       }
+
+       /* Logging not turned on for the requested zone */
+       if (!DO_LOGGING(zone_ptr)) {
+               return KERN_FAILURE;
+       }
+
+       /* Allocate memory for btlog records */
+       numrecs = (unsigned int)(get_btlog_records_count(zone_ptr->zlog_btlog));
+       recs_size = round_page(numrecs * sizeof *recs);
+
+       kr = kmem_alloc_pageable(ipc_kernel_map, &recs_addr, recs_size, VM_KERN_MEMORY_IPC);
+       if (kr != KERN_SUCCESS) {
+               return kr;
+       }
+
+       /*
+        * We will call get_btlog_records() below which populates this region while holding a spinlock
+        * (the btlog lock). So these pages need to be wired.
+        */
+       kr = vm_map_wire_kernel(ipc_kernel_map, recs_addr, recs_addr + recs_size,
+           VM_PROT_READ | VM_PROT_WRITE, VM_KERN_MEMORY_IPC, FALSE);
+       assert(kr == KERN_SUCCESS);
+
+       recs = (zone_btrecord_t *)recs_addr;
+       get_btlog_records(zone_ptr->zlog_btlog, recs, &numrecs);
+
+       kr = vm_map_unwire(ipc_kernel_map, recs_addr, recs_addr + recs_size, FALSE);
+       assert(kr == KERN_SUCCESS);
+
+       *recsp = (zone_btrecord_t *) create_vm_map_copy(recs_addr, recs_size, numrecs * sizeof *recs);
+       *recsCntp = numrecs;
+
+       return KERN_SUCCESS;
+
+#else /* DEBUG || DEVELOPMENT */
+#pragma unused(host, name, recsp, recsCntp)
+       return KERN_FAILURE;
+#endif /* DEBUG || DEVELOPMENT */
 }
 
+
 #if DEBUG || DEVELOPMENT
 
 kern_return_t
 mach_memory_info_check(void)
 {
-    mach_memory_info_t * memory_info;
-    mach_memory_info_t * info;
-       zone_t                       zone;
-    unsigned int         idx, num_info, max_zones;
-       vm_offset_t                  memory_info_addr;
+       mach_memory_info_t * memory_info;
+       mach_memory_info_t * info;
+       zone_t                       zone;
+       unsigned int         idx, num_info, max_zones;
+       vm_offset_t                  memory_info_addr;
        kern_return_t        kr;
-    size_t               memory_info_size, memory_info_vmsize;
+       size_t               memory_info_size, memory_info_vmsize;
        uint64_t             top_wired, zonestotal, total;
 
        num_info = vm_page_diagnose_estimate();
        memory_info_size = num_info * sizeof(*memory_info);
        memory_info_vmsize = round_page(memory_info_size);
        kr = kmem_alloc(kernel_map, &memory_info_addr, memory_info_vmsize, VM_KERN_MEMORY_DIAG);
-       assert (kr == KERN_SUCCESS);
+       assert(kr == KERN_SUCCESS);
 
        memory_info = (mach_memory_info_t *) memory_info_addr;
        vm_page_diagnose(memory_info, num_info, 0);
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
        max_zones = num_zones;
        simple_unlock(&all_zones_lock);
 
-    top_wired = total = zonestotal = 0;
-       for (idx = 0; idx < max_zones; idx++)
-       {
+       top_wired = total = zonestotal = 0;
+       for (idx = 0; idx < max_zones; idx++) {
                zone = &(zone_array[idx]);
                assert(zone != ZONE_NULL);
                lock_zone(zone);
-        zonestotal += ptoa_64(zone->page_count);
+               zonestotal += ptoa_64(zone->page_count);
                unlock_zone(zone);
        }
-    for (idx = 0; idx < num_info; idx++)
-    {
+       for (idx = 0; idx < num_info; idx++) {
                info = &memory_info[idx];
-               if (!info->size) continue;
-               if (VM_KERN_COUNT_WIRED == info->site) top_wired = info->size;
-               if (VM_KERN_SITE_HIDE & info->flags) continue;
-               if (!(VM_KERN_SITE_WIRED & info->flags)) continue;
+               if (!info->size) {
+                       continue;
+               }
+               if (VM_KERN_COUNT_WIRED == info->site) {
+                       top_wired = info->size;
+               }
+               if (VM_KERN_SITE_HIDE & info->flags) {
+                       continue;
+               }
+               if (!(VM_KERN_SITE_WIRED & info->flags)) {
+                       continue;
+               }
                total += info->size;
-    }
+       }
        total += zonestotal;
 
        printf("vm_page_diagnose_check %qd of %qd, zones %qd, short 0x%qx\n", total, top_wired, zonestotal, top_wired - total);
 
-    kmem_free(kernel_map, memory_info_addr, memory_info_vmsize);
+       kmem_free(kernel_map, memory_info_addr, memory_info_vmsize);
 
-    return (kr);
+       return kr;
 }
 
+extern boolean_t(*volatile consider_buffer_cache_collect)(int);
+
 #endif /* DEBUG || DEVELOPMENT */
 
 kern_return_t
 mach_zone_force_gc(
        host_t host)
 {
-       if (host == HOST_NULL)
+       if (host == HOST_NULL) {
                return KERN_INVALID_HOST;
+       }
 
 #if DEBUG || DEVELOPMENT
+       /* Callout to buffer cache GC to drop elements in the apfs zones */
+       if (consider_buffer_cache_collect != NULL) {
+               (void)(*consider_buffer_cache_collect)(0);
+       }
        consider_zone_gc(FALSE);
 #endif /* DEBUG || DEVELOPMENT */
-       return (KERN_SUCCESS);
+       return KERN_SUCCESS;
 }
 
 extern unsigned int stack_total;
 extern unsigned long long stack_allocs;
 
-#if defined(__i386__) || defined (__x86_64__)
-extern unsigned int inuse_ptepages_count;
-extern long long alloc_ptepages_count;
-#endif
-
 zone_t
 zone_find_largest(void)
 {
        unsigned int    i;
        unsigned int    max_zones;
-       zone_t          the_zone;
+       zone_t          the_zone;
        zone_t          zone_largest;
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
        max_zones = num_zones;
        simple_unlock(&all_zones_lock);
-       
+
        zone_largest = &(zone_array[0]);
        for (i = 0; i < max_zones; i++) {
                the_zone = &(zone_array[i]);
@@ -4178,17 +4825,17 @@ zone_find_largest(void)
        return zone_largest;
 }
 
-#if    ZONE_DEBUG
+#if     ZONE_DEBUG
 
 /* should we care about locks here ? */
 
-#define zone_in_use(z)         ( z->count || z->free_elements \
-                                                 || !queue_empty(&z->pages.all_free) \
-                                                 || !queue_empty(&z->pages.intermediate) \
-                                                 || (z->allows_foreign && !queue_empty(&z->pages.any_free_foreign)))
+#define zone_in_use(z)  ( z->count || z->free_elements \
+                                                 || !queue_empty(&z->pages.all_free) \
+                                                 || !queue_empty(&z->pages.intermediate) \
+                                                 || (z->allows_foreign && !queue_empty(&z->pages.any_free_foreign)))
 
 
-#endif /* ZONE_DEBUG */
+#endif  /* ZONE_DEBUG */
 
 
 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
@@ -4198,156 +4845,169 @@ zone_find_largest(void)
 static uintptr_t *
 zone_copy_all_allocations_inqueue(zone_t z, queue_head_t * queue, uintptr_t * elems)
 {
-    struct zone_page_metadata *page_meta;
-    vm_offset_t free, elements;
-    vm_offset_t idx, numElements, freeCount, bytesAvail, metaSize;
-
-    queue_iterate(queue, page_meta, struct zone_page_metadata *, pages)
-    {
-        elements = get_zone_page(page_meta);
-        bytesAvail = ptoa(page_meta->page_count);
-        freeCount = 0;
-        if (z->allows_foreign && !from_zone_map(elements, z->elem_size))
-        {
-            metaSize    = (sizeof(struct zone_page_metadata) + ZONE_ELEMENT_ALIGNMENT - 1) & ~(ZONE_ELEMENT_ALIGNMENT - 1);
-            bytesAvail -= metaSize;
-            elements   += metaSize;
-        }
-        numElements = bytesAvail / z->elem_size;
-        // construct array of all possible elements
-        for (idx = 0; idx < numElements; idx++)
-        {
-            elems[idx] = INSTANCE_PUT(elements + idx * z->elem_size);
-        }
-        // remove from the array all free elements
-        free = (vm_offset_t)page_metadata_get_freelist(page_meta);
-        while (free)
-        {
-            // find idx of free element
-            for (idx = 0; (idx < numElements) && (elems[idx] != INSTANCE_PUT(free)); idx++)  {}
-            assert(idx < numElements);
-            // remove it
-            bcopy(&elems[idx + 1], &elems[idx], (numElements - (idx + 1)) * sizeof(elems[0]));
-            numElements--;
-            freeCount++;
-            // next free element
-            vm_offset_t *primary = (vm_offset_t *) free;
-            free = *primary ^ zp_nopoison_cookie;
-        }
-        elems += numElements;
-    }
-
-    return (elems);
+       struct zone_page_metadata *page_meta;
+       vm_offset_t free, elements;
+       vm_offset_t idx, numElements, freeCount, bytesAvail, metaSize;
+
+       queue_iterate(queue, page_meta, struct zone_page_metadata *, pages)
+       {
+               elements = get_zone_page(page_meta);
+               bytesAvail = ptoa(page_meta->page_count);
+               freeCount = 0;
+               if (z->allows_foreign && !from_zone_map(elements, z->elem_size)) {
+                       metaSize    = (sizeof(struct zone_page_metadata) + ZONE_ELEMENT_ALIGNMENT - 1) & ~(ZONE_ELEMENT_ALIGNMENT - 1);
+                       bytesAvail -= metaSize;
+                       elements   += metaSize;
+               }
+               numElements = bytesAvail / z->elem_size;
+               // construct array of all possible elements
+               for (idx = 0; idx < numElements; idx++) {
+                       elems[idx] = INSTANCE_PUT(elements + idx * z->elem_size);
+               }
+               // remove from the array all free elements
+               free = (vm_offset_t)page_metadata_get_freelist(page_meta);
+               while (free) {
+                       // find idx of free element
+                       for (idx = 0; (idx < numElements) && (elems[idx] != INSTANCE_PUT(free)); idx++) {
+                       }
+                       assert(idx < numElements);
+                       // remove it
+                       bcopy(&elems[idx + 1], &elems[idx], (numElements - (idx + 1)) * sizeof(elems[0]));
+                       numElements--;
+                       freeCount++;
+                       // next free element
+                       vm_offset_t *primary = (vm_offset_t *) free;
+                       free = *primary ^ zp_nopoison_cookie;
+               }
+               elems += numElements;
+       }
+
+       return elems;
 }
 
 kern_return_t
 zone_leaks(const char * zoneName, uint32_t nameLen, leak_site_proc proc, void * refCon)
 {
-       uintptr_t         zbt[MAX_ZTRACE_DEPTH];
-    zone_t        zone;
-    uintptr_t *   array;
-    uintptr_t *   next;
-    uintptr_t     element, bt;
-    uint32_t      idx, count, found;
-    uint32_t      btidx, btcount, nobtcount, btfound;
-    uint32_t      elemSize;
-    uint64_t      maxElems;
+       uintptr_t         zbt[MAX_ZTRACE_DEPTH];
+       zone_t        zone;
+       uintptr_t *   array;
+       uintptr_t *   next;
+       uintptr_t     element, bt;
+       uint32_t      idx, count, found;
+       uint32_t      btidx, btcount, nobtcount, btfound;
+       uint32_t      elemSize;
+       uint64_t      maxElems;
        unsigned int  max_zones;
        kern_return_t kr;
 
-       simple_lock(&all_zones_lock);
+       simple_lock(&all_zones_lock, &zone_locks_grp);
        max_zones = num_zones;
        simple_unlock(&all_zones_lock);
 
-    for (idx = 0; idx < max_zones; idx++)
-    {
-        if (!strncmp(zoneName, zone_array[idx].zone_name, nameLen)) break;
-    }
-    if (idx >= max_zones) return (KERN_INVALID_NAME);
-    zone = &zone_array[idx];
-
-    elemSize = (uint32_t) zone->elem_size;
-    maxElems = ptoa(zone->page_count) / elemSize;
-
-    if ((zone->alloc_size % elemSize)
-      && !leak_scan_debug_flag) return (KERN_INVALID_CAPABILITY);
-
-    kr = kmem_alloc_kobject(kernel_map, (vm_offset_t *) &array,
-                            maxElems * sizeof(uintptr_t), VM_KERN_MEMORY_DIAG);
-    if (KERN_SUCCESS != kr) return (kr);
-
-    lock_zone(zone);
-
-    next = array;
-    next = zone_copy_all_allocations_inqueue(zone, &zone->pages.any_free_foreign, next);
-    next = zone_copy_all_allocations_inqueue(zone, &zone->pages.intermediate,     next);
-    next = zone_copy_all_allocations_inqueue(zone, &zone->pages.all_used,         next);
-    count = (uint32_t)(next - array);
-
-    unlock_zone(zone);
-
-    zone_leaks_scan(array, count, (uint32_t)zone->elem_size, &found);
-    assert(found <= count);
-
-    for (idx = 0; idx < count; idx++)
-    {
-        element = array[idx];
-        if (kInstanceFlagReferenced & element) continue;
-        element = INSTANCE_PUT(element) & ~kInstanceFlags;
-    }
-
-    if (zone->zlog_btlog && !corruption_debug_flag)
-    {
-        // btlog_copy_backtraces_for_elements will set kInstanceFlagReferenced on elements it found
-        btlog_copy_backtraces_for_elements(zone->zlog_btlog, array, &count, elemSize, proc, refCon);
-    }
-
-    for (nobtcount = idx = 0; idx < count; idx++)
-    {
-        element = array[idx];
-        if (!element)                          continue;
-        if (kInstanceFlagReferenced & element) continue;
-        element = INSTANCE_PUT(element) & ~kInstanceFlags;
-
-        // see if we can find any backtrace left in the element
-        btcount = (typeof(btcount)) (zone->elem_size / sizeof(uintptr_t));
-        if (btcount >= MAX_ZTRACE_DEPTH) btcount = MAX_ZTRACE_DEPTH - 1;
-        for (btfound = btidx = 0; btidx < btcount; btidx++)
-        {
-            bt = ((uintptr_t *)element)[btcount - 1 - btidx];
-            if (!VM_KERNEL_IS_SLID(bt)) break;
-            zbt[btfound++] = bt;
-        }
-        if (btfound) (*proc)(refCon, 1, elemSize, &zbt[0], btfound);
-        else         nobtcount++;
-    }
-    if (nobtcount)
-    {
-        // fake backtrace when we found nothing
-        zbt[0] = (uintptr_t) &zalloc;
-        (*proc)(refCon, nobtcount, elemSize, &zbt[0], 1);
-    }
-
-    kmem_free(kernel_map, (vm_offset_t) array, maxElems * sizeof(uintptr_t));
-
-    return (KERN_SUCCESS);
+       for (idx = 0; idx < max_zones; idx++) {
+               if (!strncmp(zoneName, zone_array[idx].zone_name, nameLen)) {
+                       break;
+               }
+       }
+       if (idx >= max_zones) {
+               return KERN_INVALID_NAME;
+       }
+       zone = &zone_array[idx];
+
+       elemSize = (uint32_t) zone->elem_size;
+       maxElems = ptoa(zone->page_count) / elemSize;
+
+       if ((zone->alloc_size % elemSize)
+           && !leak_scan_debug_flag) {
+               return KERN_INVALID_CAPABILITY;
+       }
+
+       kr = kmem_alloc_kobject(kernel_map, (vm_offset_t *) &array,
+           maxElems * sizeof(uintptr_t), VM_KERN_MEMORY_DIAG);
+       if (KERN_SUCCESS != kr) {
+               return kr;
+       }
+
+       lock_zone(zone);
+
+       next = array;
+       next = zone_copy_all_allocations_inqueue(zone, &zone->pages.any_free_foreign, next);
+       next = zone_copy_all_allocations_inqueue(zone, &zone->pages.intermediate, next);
+       next = zone_copy_all_allocations_inqueue(zone, &zone->pages.all_used, next);
+       count = (uint32_t)(next - array);
+
+       unlock_zone(zone);
+
+       zone_leaks_scan(array, count, (uint32_t)zone->elem_size, &found);
+       assert(found <= count);
+
+       for (idx = 0; idx < count; idx++) {
+               element = array[idx];
+               if (kInstanceFlagReferenced & element) {
+                       continue;
+               }
+               element = INSTANCE_PUT(element) & ~kInstanceFlags;
+       }
+
+       if (zone->zlog_btlog && !corruption_debug_flag) {
+               // btlog_copy_backtraces_for_elements will set kInstanceFlagReferenced on elements it found
+               btlog_copy_backtraces_for_elements(zone->zlog_btlog, array, &count, elemSize, proc, refCon);
+       }
+
+       for (nobtcount = idx = 0; idx < count; idx++) {
+               element = array[idx];
+               if (!element) {
+                       continue;
+               }
+               if (kInstanceFlagReferenced & element) {
+                       continue;
+               }
+               element = INSTANCE_PUT(element) & ~kInstanceFlags;
+
+               // see if we can find any backtrace left in the element
+               btcount = (typeof(btcount))(zone->elem_size / sizeof(uintptr_t));
+               if (btcount >= MAX_ZTRACE_DEPTH) {
+                       btcount = MAX_ZTRACE_DEPTH - 1;
+               }
+               for (btfound = btidx = 0; btidx < btcount; btidx++) {
+                       bt = ((uintptr_t *)element)[btcount - 1 - btidx];
+                       if (!VM_KERNEL_IS_SLID(bt)) {
+                               break;
+                       }
+                       zbt[btfound++] = bt;
+               }
+               if (btfound) {
+                       (*proc)(refCon, 1, elemSize, &zbt[0], btfound);
+               } else {
+                       nobtcount++;
+               }
+       }
+       if (nobtcount) {
+               // fake backtrace when we found nothing
+               zbt[0] = (uintptr_t) &zalloc;
+               (*proc)(refCon, nobtcount, elemSize, &zbt[0], 1);
+       }
+
+       kmem_free(kernel_map, (vm_offset_t) array, maxElems * sizeof(uintptr_t));
+
+       return KERN_SUCCESS;
 }
 
 boolean_t
 kdp_is_in_zone(void *addr, const char *zone_name)
 {
        zone_t z;
-       return (zone_element_size(addr, &z) && !strcmp(z->zone_name, zone_name));
+       return zone_element_size(addr, &z) && !strcmp(z->zone_name, zone_name);
 }
 
 boolean_t
 run_zone_test(void)
 {
-       int i = 0, max_iter = 5;
+       unsigned int i = 0, max_iter = 5;
        void * test_ptr;
        zone_t test_zone;
 
-       simple_lock(&zone_test_lock);
+       simple_lock(&zone_test_lock, &zone_locks_grp);
        if (!zone_test_running) {
                zone_test_running = TRUE;
        } else {
@@ -4400,7 +5060,7 @@ run_zone_test(void)
 
        printf("run_zone_test: Test passed\n");
 
-       simple_lock(&zone_test_lock);
+       simple_lock(&zone_test_lock, &zone_locks_grp);
        zone_test_running = FALSE;
        simple_unlock(&zone_test_lock);