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slub: Do not dereference NULL pointer in node_match 

The variables accessed in slab_alloc are volatile and therefore
the page pointer passed to node_match can be NULL. The processing
of data in slab_alloc is tentative until either the cmpxhchg
succeeds or the __slab_alloc slowpath is invoked. Both are
able to perform the same allocation from the freelist.

Check for the NULL pointer in node_match.

A false positive will lead to a retry of the loop in __slab_alloc.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
hifive-unleashed-5.1
Christoph Lameter 2013-01-23 21:45:47 +00:00 committed by Pekka Enberg
parent 338b264229
commit 4d7868e647
1 changed files with 1 additions and 1 deletions
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2
mm/slub.c
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@ -2042,7 +2042,7 @@ static void flush_all(struct kmem_cache *s)
static inline int node_match(struct page *page, int node)
{
#ifdef CONFIG_NUMA
if (node != NUMA_NO_NODE && page_to_nid(page) != node)
if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
return 0;
#endif
return 1;