From: Christoph Lameter <[email protected]> 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 <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Pekka Enberg <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> [bigeasy@linutronix: replace page with c->page] Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
