From: Andrey Konovalov <andreyknvl@xxxxxxxxxx> [ Upstream commit 51dedad06b5f6c3eea7ec1069631b1ef7796912a ] Similarly to "kasan, slub: move kasan_poison_slab hook before page_address", move kasan_poison_slab() before alloc_slabmgmt(), which calls page_address(), to make page_address() return value to be non-tagged. This, combined with calling kasan_reset_tag() for off-slab slab management object, leads to freelist being stored non-tagged. Link: http://lkml.kernel.org/r/dfb53b44a4d00de3879a05a9f04c1f55e584f7a1.1550602886.git.andreyknvl@xxxxxxxxxx Signed-off-by: Andrey Konovalov <andreyknvl@xxxxxxxxxx> Tested-by: Qian Cai <cai@xxxxxx> Cc: Alexander Potapenko <glider@xxxxxxxxxx> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> Cc: Evgeniy Stepanov <eugenis@xxxxxxxxxx> Cc: Kostya Serebryany <kcc@xxxxxxxxxx> Cc: Vincenzo Frascino <vincenzo.frascino@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- mm/slab.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/mm/slab.c b/mm/slab.c index 409631e49295..766043dd3f8e 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -2378,6 +2378,7 @@ static void *alloc_slabmgmt(struct kmem_cache *cachep, /* Slab management obj is off-slab. */ freelist = kmem_cache_alloc_node(cachep->freelist_cache, local_flags, nodeid); + freelist = kasan_reset_tag(freelist); if (!freelist) return NULL; } else { @@ -2690,6 +2691,13 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep, offset *= cachep->colour_off; + /* + * Call kasan_poison_slab() before calling alloc_slabmgmt(), so + * page_address() in the latter returns a non-tagged pointer, + * as it should be for slab pages. + */ + kasan_poison_slab(page); + /* Get slab management. */ freelist = alloc_slabmgmt(cachep, page, offset, local_flags & ~GFP_CONSTRAINT_MASK, page_node); @@ -2698,7 +2706,6 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep, slab_map_pages(cachep, page, freelist); - kasan_poison_slab(page); cache_init_objs(cachep, page); if (gfpflags_allow_blocking(local_flags)) -- 2.19.1
