Commit 4d7868e6 authored Jan 23, 2013 by Christoph Lameter Committed by Pekka Enberg Apr 05, 2013

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>

parent 338b2642

mm/slub.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;