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.
Signed-off-by: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
Reported-by: Andrew Morton <a...@linux-foundation.org>
LKML-reference: https://lkml.org/lkml/2015/6/8/583
---
mm/slab_common.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 8873985..ea69b13 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -641,6 +641,9 @@ 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();
--
2.4.3.368.g7974889
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