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authorMatthew Wilcox (Oracle) <willy@infradead.org>2021-11-05 13:35:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 13:30:33 -0700
commit820a1e6e87ccaa6c0c77ac7d79d05beec3f8cb88 (patch)
tree63574d9076436d646ac4f95ccd1ce5d7c4280716
parentf70da745be4d4c367568b8345f50db1ae04efcb2 (diff)
kasan: fix tag for large allocations when using CONFIG_SLAB
If an object is allocated on a tail page of a multi-page slab, kasan will get the wrong tag because page->s_mem is NULL for tail pages. I'm not quite sure what the user-visible effect of this might be. Link: https://lkml.kernel.org/r/20211001024105.3217339-1-willy@infradead.org Fixes: 7f94ffbc4c6a ("kasan: add hooks implementation for tag-based mode") Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Acked-by: Marco Elver <elver@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com> Cc: Alexander Potapenko <glider@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/kasan/common.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 3e0999892c36..8428da2aaf17 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -298,7 +298,7 @@ static inline u8 assign_tag(struct kmem_cache *cache,
/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
#ifdef CONFIG_SLAB
/* For SLAB assign tags based on the object index in the freelist. */
- return (u8)obj_to_index(cache, virt_to_page(object), (void *)object);
+ return (u8)obj_to_index(cache, virt_to_head_page(object), (void *)object);
#else
/*
* For SLUB assign a random tag during slab creation, otherwise reuse