X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/316670eb35587141e969394ae8537d66b9211e80..a39ff7e25e19b3a8c3020042a3872ca9ec9659f1:/iokit/Kernel/IOStatistics.cpp?ds=inline

diff --git a/iokit/Kernel/IOStatistics.cpp b/iokit/Kernel/IOStatistics.cpp
index def362e60..f3771602a 100644
--- a/iokit/Kernel/IOStatistics.cpp
+++ b/iokit/Kernel/IOStatistics.cpp
@@ -27,7 +27,9 @@
  */
 
 #include <sys/sysctl.h>
+#include <kern/backtrace.h>
 #include <kern/host.h>
+#include <kern/zalloc.h>
 
 #include <IOKit/system.h>
 #include <libkern/c++/OSKext.h>
@@ -259,10 +261,10 @@ void IOStatistics::onKextUnload(OSKext *kext)
 		IOWorkLoopCounter *wlc;
 		IOUserClientProcessEntry *uce;
 
-		/* Free up the list of counters */
+		/* Disconnect workloop counters; cleanup takes place in unregisterWorkLoop() */
 		while ((wlc = SLIST_FIRST(&found->workLoopList))) {
 			SLIST_REMOVE_HEAD(&found->workLoopList, link);
-			kfree(wlc, sizeof(IOWorkLoopCounter));
+			wlc->parentKext = NULL;
 		}
 
 		/* Free up the user client list */
@@ -520,8 +522,9 @@ void IOStatistics::unregisterWorkLoop(IOWorkLoopCounter *counter)
 	}
 	
 	IORWLockWrite(lock);
-
-	SLIST_REMOVE(&counter->parentKext->workLoopList, counter, IOWorkLoopCounter, link);
+	if (counter->parentKext) {
+		SLIST_REMOVE(&counter->parentKext->workLoopList, counter, IOWorkLoopCounter, link);
+	}
 	kfree(counter, sizeof(IOWorkLoopCounter));
 	registeredWorkloops--;
 	
@@ -812,8 +815,11 @@ int IOStatistics::getUserClientStatistics(sysctl_req *req)
 		goto exit;
 	}
 
-	SYSCTL_IN(req, &requestedLoadTag, sizeof(requestedLoadTag));
-	
+	error = SYSCTL_IN(req, &requestedLoadTag, sizeof(requestedLoadTag));
+	if (error) {
+		goto exit;
+	}
+
 	LOG(2, "IOStatistics::getUserClientStatistics - requesting kext w/load tag: %d\n", requestedLoadTag);
 
 	buffer = (char*)kalloc(calculatedSize);
@@ -1213,8 +1219,13 @@ KextNode *IOStatistics::getKextNodeFromBacktrace(boolean_t write) {
 	vm_offset_t *scanAddr = NULL;
 	uint32_t i;
 	KextNode *found = NULL, *ke = NULL;
-    
-	btCount = OSBacktrace(bt, btCount);
+
+	/*
+	 * Gathering the backtrace is a significant source of
+	 * overhead. OSBacktrace does many safety checks that
+	 * are not needed in this situation.
+	 */
+	btCount = backtrace((uintptr_t*)bt, btCount);
 
 	if (write) {
 		IORWLockWrite(lock);