| kdp-reenter Schedule reentry into the debugger and continue.
| kdp-reboot Restart remote target
|
+| zstack Print zalloc caller stack (zone leak debugging)
+| findoldest Find oldest zone leak debugging record
+| countpcs Print how often a pc occurs in the zone leak log
+|
+|
| Type "help <macro>" for more specific help on a particular macro.
| Type "show user <macro>" to see what the macro is really doing.
end
define showcurrentthreads
set $kgm_prp = (struct processor *)processor_list
while $kgm_prp != 0
+ printf "Processor 0x%08x State %d (cpu_id %x)\n", $kgm_prp, ($kgm_prp)->state, ($kgm_prp)->cpu_num
if ($kgm_prp)->active_thread != 0
set $kgm_actp = ($kgm_prp)->active_thread
showtaskheader
define showcurrentstacks
set $kgm_prp = processor_list
while $kgm_prp != 0
+ printf "Processor 0x%08x State %d (cpu_id %x)\n", $kgm_prp, ($kgm_prp)->state, ($kgm_prp)->cpu_num
if ($kgm_prp)->active_thread != 0
set $kgm_actp = ($kgm_prp)->active_thread
showtaskheader
set $kgm_obj = (OSObject *) $arg1
set $kgm_vt = *((void **) $arg1)
+ if ($kgm_mtype == 12)
+ set $kgm_vt = $kgm_vt - 2 * sizeof(void *)
+ end
+
if ($kgm_show_object_addrs)
printf "`object %p, vt ", $arg1
output /a (unsigned) $kgm_vt
printf " <object %p, ", $kgm_re
printf "vtable "
set $kgm_vt = (unsigned) *(void**) $kgm_re
+ if ($kgm_mtype == 12)
+ set $kgm_vt = $kgm_vt - 2 * sizeof(void *)
+ end
output /a $kgm_vt
if ($kgm_vt != _ZTV15IORegistryEntry)
| For page-tables in <pmap> translate <virtual_address> to physical address.
end
+define zstack
+ set $index = $arg0
+
+ if (log_records == 0)
+ set $count = 0
+ printf "Zone logging not enabled. Add 'zlog=<zone name>' to boot-args.\n"
+ else
+ if ($argc == 2)
+ set $count = $arg1
+ else
+ set $count = 1
+ end
+ end
+
+ while ($count)
+ printf "\n--------------- "
+
+ if (zrecords[$index].z_opcode == 1)
+ printf "ALLOC "
+ else
+ printf "FREE "
+ end
+
+ printf " 0x%x : index %d : ztime %d -------------\n", zrecords[$index].z_element, $index, zrecords[$index].z_time
+
+ set $frame = 0
+
+ while ($frame < 15)
+ set $frame_pc = zrecords[$index].z_pc[$frame]
+
+ if ($frame_pc == 0)
+ loop_break
+ end
+
+ x/i $frame_pc
+ set $frame = $frame + 1
+ end
+
+ set $index = $index + 1
+ set $count = $count - 1
+ end
+end
+
+document zstack
+Syntax: (gdb) zstack <index> [<count>]
+| Zone leak debugging: print the stack trace of log element at <index>.
+| If a <count> is supplied, it prints <count> log elements starting at <index>.
+|
+| The suggested usage is to look at indexes below zcurrent and look for common stack traces.
+| The stack trace that occurs the most is probably the cause of the leak. Find the pc of the
+| function calling into zalloc and use the countpcs kgmacro to find out how often that pc occurs in the log.
+| The pc occuring in a high percentage of records is most likely the source of the leak.
+|
+| The findoldest kgmacro is also useful for leak debugging since it identifies the oldest record
+| in the log, which may indicate the leaker.
+end
+
+define findoldest
+ set $index = 0
+ set $count = log_records
+ set $cur_min = 2000000000
+ set $cur_index = 0
+
+ if (log_records == 0)
+ printf "Zone logging not enabled. Add 'zlog=<zone name>' to boot-args.\n"
+ else
+
+ while ($count)
+ if (zrecords[$index].z_element && zrecords[$index].z_time < $cur_min)
+ set $cur_index = $index
+ set $cur_min = zrecords[$index].z_time
+ end
+
+ set $count = $count - 1
+ set $index = $index + 1
+ end
+
+ printf "oldest record is at log index %d:\n", $cur_index
+ zstack $cur_index
+ end
+end
+
+document findoldest
+Syntax: (gdb) findoldest
+| Zone leak debugging: find and print the oldest record in the log. Note that this command
+| can take several minutes to run since it uses linear search.
+|
+| Once it prints a stack trace, find the pc of the caller above all the zalloc, kalloc and
+| IOKit layers. Then use the countpcs kgmacro to see how often this caller has allocated
+| memory. A caller with a high percentage of records in the log is probably the leaker.
+end
+
+define countpcs
+ set $target_pc = $arg0
+ set $index = 0
+ set $count = log_records
+ set $found = 0
+
+ if (log_records == 0)
+ printf "Zone logging not enabled. Add 'zlog=<zone name>' to boot-args.\n"
+ else
+
+ while ($count)
+ set $frame = 0
+
+ if (zrecords[$index].z_element != 0)
+ while ($frame < 15)
+ if (zrecords[$index].z_pc[$frame] == $target_pc)
+ set $found = $found + 1
+ set $frame = 15
+ end
+
+ set $frame = $frame + 1
+ end
+ end
+
+ set $index = $index + 1
+ set $count = $count - 1
+ end
+
+ printf "occurred %d times in log (%d%c of records)\n", $found, ($found * 100) / zrecorded, '%'
+ end
+end
+
+document countpcs
+Syntax: (gdb) countpcs <pc>
+| Zone leak debugging: search the log and print a count of all log entries that contain the given <pc>
+| in the stack trace. This is useful for verifying a suspected <pc> as being the source of
+| the leak. If a high percentage of the log entries contain the given <pc>, then it's most
+| likely the source of the leak. Note that this command can take several minutes to run.
+end
+
+define findelem
+ set $fe_index = zcurrent
+ set $fe_count = log_records
+ set $fe_elem = $arg0
+ set $fe_prev_op = -1
+
+ if (log_records == 0)
+ printf "Zone logging not enabled. Add 'zlog=<zone name>' to boot-args.\n"
+ end
+
+ while ($fe_count)
+ if (zrecords[$fe_index].z_element == $fe_elem)
+ zstack $fe_index
+
+ if (zrecords[$fe_index].z_opcode == $fe_prev_op)
+ printf "*************** DOUBLE OP! *********************\n
+ end
+
+ set $fe_prev_op = zrecords[$fe_index].z_opcode
+ end
+
+ set $fe_count = $fe_count - 1
+ set $fe_index = $fe_index + 1
+
+ if ($fe_index >= log_records)
+ set $fe_index = 0
+ end
+ end
+end
+
+document findelem
+Syntax: (gdb) findelem <elem addr>
+| Zone corruption debugging: search the log and print out the stack traces for all log entries that
+| refer to the given zone element. When the kernel panics due to a corrupted zone element, get the
+| element address and use this macro. This will show you the stack traces of all logged zalloc and
+| zfree operations which tells you who touched the element in the recent past. This also makes
+| double-frees readily apparent.
+end
projects / apple / xnu.git / blobdiff