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authorJoonsoo Kim <iamjoonsoo.kim@lge.com>2016-03-16 00:55:12 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-16 02:55:16 +0300
commitd86bd1bece6fc41d59253002db5441fe960a37f6 (patch)
tree3881125eb61ec76b5ad87d6a7e9f51061b76e7e6 /include/linux/slub_def.h
parent149daaf3a02c020ddae64668c3a1bd0c4f314d6a (diff)
downloadlinux-d86bd1bece6fc41d59253002db5441fe960a37f6.tar.xz
mm/slub: support left redzone
SLUB already has a redzone debugging feature. But it is only positioned at the end of object (aka right redzone) so it cannot catch left oob. Although current object's right redzone acts as left redzone of next object, first object in a slab cannot take advantage of this effect. This patch explicitly adds a left red zone to each object to detect left oob more precisely. Background: Someone complained to me that left OOB doesn't catch even if KASAN is enabled which does page allocation debugging. That page is out of our control so it would be allocated when left OOB happens and, in this case, we can't find OOB. Moreover, SLUB debugging feature can be enabled without page allocator debugging and, in this case, we will miss that OOB. Before trying to implement, I expected that changes would be too complex, but, it doesn't look that complex to me now. Almost changes are applied to debug specific functions so I feel okay. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/slub_def.h')
-rw-r--r--include/linux/slub_def.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index b7e57927f521..ac5143f95ee6 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -81,6 +81,7 @@ struct kmem_cache {
int reserved; /* Reserved bytes at the end of slabs */
const char *name; /* Name (only for display!) */
struct list_head list; /* List of slab caches */
+ int red_left_pad; /* Left redzone padding size */
#ifdef CONFIG_SYSFS
struct kobject kobj; /* For sysfs */
#endif