From: Miaohe Lin Date: Mon, 18 Oct 2021 22:15:55 +0000 (-0700) Subject: mm, slub: fix mismatch between reconstructed freelist depth and cnt X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=899447f669da76cc3605665e1a95ee877bc464cc;p=linux.git mm, slub: fix mismatch between reconstructed freelist depth and cnt If object's reuse is delayed, it will be excluded from the reconstructed freelist. But we forgot to adjust the cnt accordingly. So there will be a mismatch between reconstructed freelist depth and cnt. This will lead to free_debug_processing() complaining about freelist count or a incorrect slub inuse count. Link: https://lkml.kernel.org/r/20210916123920.48704-3-linmiaohe@huawei.com Fixes: c3895391df38 ("kasan, slub: fix handling of kasan_slab_free hook") Signed-off-by: Miaohe Lin Reviewed-by: Vlastimil Babka Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Bharata B Rao Cc: Christoph Lameter Cc: David Rientjes Cc: Faiyaz Mohammed Cc: Greg Kroah-Hartman Cc: Joonsoo Kim Cc: Kees Cook Cc: Pekka Enberg Cc: Roman Gushchin Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/slub.c b/mm/slub.c index ed160b6c54f8d..a56a6423d4e88 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1701,7 +1701,8 @@ static __always_inline bool slab_free_hook(struct kmem_cache *s, } static inline bool slab_free_freelist_hook(struct kmem_cache *s, - void **head, void **tail) + void **head, void **tail, + int *cnt) { void *object; @@ -1728,6 +1729,12 @@ static inline bool slab_free_freelist_hook(struct kmem_cache *s, *head = object; if (!*tail) *tail = object; + } else { + /* + * Adjust the reconstructed freelist depth + * accordingly if object's reuse is delayed. + */ + --(*cnt); } } while (object != old_tail); @@ -3480,7 +3487,7 @@ static __always_inline void slab_free(struct kmem_cache *s, struct page *page, * With KASAN enabled slab_free_freelist_hook modifies the freelist * to remove objects, whose reuse must be delayed. */ - if (slab_free_freelist_hook(s, &head, &tail)) + if (slab_free_freelist_hook(s, &head, &tail, &cnt)) do_slab_free(s, page, head, tail, cnt, addr); }