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MDEV-17799 Add ASAN-poisoned redzones for MEM_ROOT and mem_heap_t

This patch is for MEM_ROOT only.
In debug mode add 8 byte of poisoned memory before every allocated chunk.
On the right of every chunk there will be either 1-7 trailing poisoned bytes, or
next chunk's redzone, or poisoned non allocated memory or redzone of a
malloc()ed buffer.
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kevgs authored and vuvova committed Nov 28, 2018
1 parent 2c9844a commit 7b59ec6f345986db0cbc6f8b1d504a6e7e21cb5f
Showing with 9 additions and 1 deletion.
  1. +7 −0 include/my_valgrind.h
  2. +2 −1 mysys/my_alloc.c
@@ -13,6 +13,9 @@
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */

#ifndef _my_valgrind_h
#define _my_valgrind_h

/* clang -> gcc */
#ifndef __has_feature
# define __has_feature(x) 0
@@ -49,9 +52,13 @@
#endif /* HAVE_VALGRIND */

#ifndef DBUG_OFF
static const size_t REDZONE_SIZE= 8;
#define TRASH_FILL(A,B,C) do { const size_t trash_tmp= (B); MEM_UNDEFINED(A, trash_tmp); memset(A, C, trash_tmp); } while (0)
#else
static const size_t REDZONE_SIZE= 0;
#define TRASH_FILL(A,B,C) do { MEM_UNDEFINED((A), (B)); } while (0)
#endif
#define TRASH_ALLOC(A,B) do { TRASH_FILL(A,B,0xA5); MEM_UNDEFINED(A,B); } while(0)
#define TRASH_FREE(A,B) do { TRASH_FILL(A,B,0x8F); MEM_NOACCESS(A,B); } while(0)

#endif /* _my_valgrind_h */
@@ -197,7 +197,7 @@ void *alloc_root(MEM_ROOT *mem_root, size_t length)
DBUG_SET("-d,simulate_out_of_memory");
DBUG_RETURN((void*) 0); /* purecov: inspected */
});
length= ALIGN_SIZE(length);
length= ALIGN_SIZE(length) + REDZONE_SIZE;
if ((*(prev= &mem_root->free)) != NULL)
{
if ((*prev)->left < length &&
@@ -242,6 +242,7 @@ void *alloc_root(MEM_ROOT *mem_root, size_t length)
mem_root->used= next;
mem_root->first_block_usage= 0;
}
point+= REDZONE_SIZE;
TRASH_ALLOC(point, original_length);
DBUG_PRINT("exit",("ptr: 0x%lx", (ulong) point));
DBUG_RETURN((void*) point);

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