Messages in this thread Patch in this message | | | From | Sebastian Andrzej Siewior <> | Subject | [PATCH 09/16] FIX [1/2] slub: Do not dereference NULL pointer in node_match | Date | Wed, 13 Feb 2013 17:12:04 +0100 |
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From: Christoph Lameter <cl@linux.com>
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> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> [bigeasy@linutronix: replace page with c->page] Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- mm/slub.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/slub.c b/mm/slub.c index 5710788..08eb4c1 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2038,7 +2038,7 @@ static void flush_all(struct kmem_cache *s) static inline int node_match(struct kmem_cache_cpu *c, int node) { #ifdef CONFIG_NUMA - if (node != NUMA_NO_NODE && c->node != node) + if (!c->page || (node != NUMA_NO_NODE && c->node != node)) return 0; #endif return 1; -- 1.7.10.4
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