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Add backtrace generation to MALLOC_DEBUG memory corruption reports

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This patch allows astmm to access the backtrace generation code in Asterisk.
When memory is allocated, a backtrace is created and stored with the memory
region that tracks the allocation. If a memory corruption is detected, the
backtrace is printed to the astmm log. The backtrace will make use of the
BETTER_BACKTRACES build option if available.

As a result, this patch moves the backtrace generation code into its own file
and uses the non-wrapped versions of the C library memory allocation routines.
This allows the memory allocation code to safely use the backtrace generation
routines without infinitely recursing.

Review: https://reviewboard.asterisk.org/r/2567


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@391012 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Matthew Jordan
2013-06-08 22:09:07 +00:00
parent 2fe6b6a533
commit c43f380d03
8 changed files with 360 additions and 256 deletions
Download Patch File Download Diff File Expand all files Collapse all files

29
main/astmm.c
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@@ -42,6 +42,7 @@ ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
#include "asterisk/lock.h"
#include "asterisk/strings.h"
#include "asterisk/unaligned.h"
#include "asterisk/backtrace.h"
/*!
* The larger the number the faster memory can be freed.
@@ -78,13 +79,13 @@ static FILE *mmlog;
struct ast_region {
AST_LIST_ENTRY(ast_region) node;
struct ast_bt *bt;
size_t len;
unsigned int cache; /* region was allocated as part of a cache pool */
unsigned int lineno;
enum func_type which;
char file[64];
char func[40];
/*!
* \brief Lower guard fence.
*
@@ -157,6 +158,25 @@ AST_MUTEX_DEFINE_STATIC_NOTRACKING(reglock);
} \
} while (0)
static void print_backtrace(struct ast_bt *bt)
{
int i = 0;
char **strings;
if (!bt) {
return;
}
if ((strings = ast_bt_get_symbols(bt->addresses, bt->num_frames))) {
astmm_log("Memory allocation backtrace:\n");
for (i = 3; i < bt->num_frames - 2; i++) {
astmm_log("#%d: [%p] %s\n", i - 3, bt->addresses[i], strings[i]);
}
free(strings);
}
}
/*!
* \internal
*
@@ -191,6 +211,7 @@ static void *__ast_alloc_region(size_t size, const enum func_type which, const c
reg->cache = cache;
reg->lineno = lineno;
reg->which = which;
reg->bt = ast_bt_create();
ast_copy_string(reg->file, file, sizeof(reg->file));
ast_copy_string(reg->func, func, sizeof(reg->func));
@@ -262,6 +283,7 @@ static void region_data_check(struct ast_region *reg)
if (*pos != FREED_MAGIC) {
astmm_log("WARNING: Memory corrupted after free of %p allocated at %s %s() line %d\n",
reg->data, reg->file, reg->func, reg->lineno);
print_backtrace(reg->bt);
my_do_crash();
break;
}
@@ -321,6 +343,9 @@ static void region_free(struct ast_freed_regions *freed, struct ast_region *reg)
if (old) {
region_data_check(old);
if (old->bt) {
old->bt = ast_bt_destroy(old->bt);
}
free(old);
}
}
@@ -380,12 +405,14 @@ static void region_check_fences(struct ast_region *reg)
if (*fence != FENCE_MAGIC) {
astmm_log("WARNING: Low fence violation of %p allocated at %s %s() line %d\n",
reg->data, reg->file, reg->func, reg->lineno);
print_backtrace(reg->bt);
my_do_crash();
}
fence = (unsigned int *) (reg->data + reg->len);
if (get_unaligned_uint32(fence) != FENCE_MAGIC) {
astmm_log("WARNING: High fence violation of %p allocated at %s %s() line %d\n",
reg->data, reg->file, reg->func, reg->lineno);
print_backtrace(reg->bt);
my_do_crash();
}
}