From b3cbd9bf77cd1888114dbee1653e79aa23fd4068 Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Tue, 2 Aug 2016 14:02:52 -0700 Subject: mm/kasan: get rid of ->state in struct kasan_alloc_meta The state of object currently tracked in two places - shadow memory, and the ->state field in struct kasan_alloc_meta. We can get rid of the latter. The will save us a little bit of memory. Also, this allow us to move free stack into struct kasan_alloc_meta, without increasing memory consumption. So now we should always know when the last time the object was freed. This may be useful for long delayed use-after-free bugs. As a side effect this fixes following UBSAN warning: UBSAN: Undefined behaviour in mm/kasan/quarantine.c:102:13 member access within misaligned address ffff88000d1efebc for type 'struct qlist_node' which requires 8 byte alignment Link: http://lkml.kernel.org/r/1470062715-14077-5-git-send-email-aryabinin@virtuozzo.com Reported-by: kernel test robot Signed-off-by: Andrey Ryabinin Cc: Alexander Potapenko Cc: Dmitry Vyukov Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/kasan/kasan.h | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) (limited to 'mm/kasan/kasan.h') diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index aa175460c8f9..9b7b31e25fd2 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -59,13 +59,6 @@ struct kasan_global { * Structures to keep alloc and free tracks * */ -enum kasan_state { - KASAN_STATE_INIT, - KASAN_STATE_ALLOC, - KASAN_STATE_QUARANTINE, - KASAN_STATE_FREE -}; - #define KASAN_STACK_DEPTH 64 struct kasan_track { @@ -74,8 +67,8 @@ struct kasan_track { }; struct kasan_alloc_meta { - struct kasan_track track; - u32 state; + struct kasan_track alloc_track; + struct kasan_track free_track; }; struct qlist_node { @@ -86,7 +79,6 @@ struct kasan_free_meta { * Otherwise it might be used for the allocator freelist. */ struct qlist_node quarantine_link; - struct kasan_track track; }; struct kasan_alloc_meta *get_alloc_info(struct kmem_cache *cache, -- cgit v1.2.3