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Subject[PATCH AUTOSEL 4.14 19/33] kasan, slub: move kasan_poison_slab hook before page_address
Date
From: Andrey Konovalov <andreyknvl@google.com>

[ Upstream commit a71012242837fe5e67d8c999cfc357174ed5dba0 ]

With tag based KASAN page_address() looks at the page flags to see whether
the resulting pointer needs to have a tag set. Since we don't want to set
a tag when page_address() is called on SLAB pages, we call
page_kasan_tag_reset() in kasan_poison_slab(). However in allocate_slab()
page_address() is called before kasan_poison_slab(). Fix it by changing
the order.

[andreyknvl@google.com: fix compilation error when CONFIG_SLUB_DEBUG=n]
Link: http://lkml.kernel.org/r/ac27cc0bbaeb414ed77bcd6671a877cf3546d56e.1550066133.git.andreyknvl@google.com
Link: http://lkml.kernel.org/r/cd895d627465a3f1c712647072d17f10883be2a1.1549921721.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgeniy Stepanov <eugenis@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Kostya Serebryany <kcc@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
mm/slub.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index 220d42e592ef..f14ef59c9e57 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1087,6 +1087,16 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page,
init_tracking(s, object);
}

+static void setup_page_debug(struct kmem_cache *s, void *addr, int order)
+{
+ if (!(s->flags & SLAB_POISON))
+ return;
+
+ metadata_access_enable();
+ memset(addr, POISON_INUSE, PAGE_SIZE << order);
+ metadata_access_disable();
+}
+
static inline int alloc_consistency_checks(struct kmem_cache *s,
struct page *page,
void *object, unsigned long addr)
@@ -1304,6 +1314,8 @@ unsigned long kmem_cache_flags(unsigned long object_size,
#else /* !CONFIG_SLUB_DEBUG */
static inline void setup_object_debug(struct kmem_cache *s,
struct page *page, void *object) {}
+static inline void setup_page_debug(struct kmem_cache *s,
+ void *addr, int order) {}

static inline int alloc_debug_processing(struct kmem_cache *s,
struct page *page, void *object, unsigned long addr) { return 0; }
@@ -1599,12 +1611,11 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
if (page_is_pfmemalloc(page))
SetPageSlabPfmemalloc(page);

- start = page_address(page);
+ kasan_poison_slab(page);

- if (unlikely(s->flags & SLAB_POISON))
- memset(start, POISON_INUSE, PAGE_SIZE << order);
+ start = page_address(page);

- kasan_poison_slab(page);
+ setup_page_debug(s, start, order);

shuffle = shuffle_freelist(s, page);

--
2.19.1
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