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authorSergey Senozhatsky <sergey.senozhatsky@gmail.com>2015-09-08 15:00:50 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-08 15:35:28 -0700
commit3942d29918522ba6a393c19388301ec04df429cd (patch)
tree7280b6114b6d794e306c7039b1dcd92852b8de01 /mm/slab_common.c
parent75e8f8b24cb0dc4951267d31f0a49e5ce2f345c4 (diff)
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mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()
kmem_cache_destroy() does not tolerate a NULL kmem_cache pointer argument and performs a NULL-pointer dereference. This requires additional attention and effort from developers/reviewers and forces all kmem_cache_destroy() callers (200+ as of 4.1) to do a NULL check if (cache) kmem_cache_destroy(cache); Or, otherwise, be invalid kmem_cache_destroy() users. Tweak kmem_cache_destroy() and NULL-check the pointer there. Proposed by Andrew Morton. Link: https://lkml.org/lkml/2015/6/8/583 Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Julia Lawall <julia.lawall@lip6.fr> Cc: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r--mm/slab_common.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index c26829fe4e37..bde04a699ab6 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -640,6 +640,9 @@ void kmem_cache_destroy(struct kmem_cache *s)
bool need_rcu_barrier = false;
bool busy = false;
+ if (unlikely(!s))
+ return;
+
BUG_ON(!is_root_cache(s));
get_online_cpus();