From 14e50c6a9bc2b283bb4021026226268312ceefdd Mon Sep 17 00:00:00 2001 From: Aaron Tomlin Date: Fri, 26 Apr 2013 16:15:34 +0100 Subject: [PATCH] mm: slab: Verify the nodeid passed to ____cache_alloc_node If the nodeid is > num_online_nodes() this can cause an Oops and a panic(). The purpose of this patch is to assert if this condition is true to aid debugging efforts rather than some random NULL pointer dereference or page fault. This patch is in response to BZ#42967 [1]. Using VM_BUG_ON so it's used only when CONFIG_DEBUG_VM is set, given that ____cache_alloc_node() is a hot code path. [1]: https://bugzilla.kernel.org/show_bug.cgi?id=42967 Signed-off-by: Aaron Tomlin Reviewed-by: Rik van Riel Acked-by: Christoph Lameter Acked-by: Rafael Aquini Acked-by: David Rientjes Signed-off-by: Pekka Enberg --- mm/slab.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/slab.c b/mm/slab.c index 910df6326831..a98f8db93670 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3289,6 +3289,7 @@ static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, void *obj; int x; + VM_BUG_ON(nodeid > num_online_nodes()); n = cachep->node[nodeid]; BUG_ON(!n); -- 2.20.1