From: Steven Rostedt Date: Thu, 17 Jan 2013 17:13:46 +0000 (-0500) Subject: slob: Check for NULL pointer before calling ctor() X-Git-Tag: v3.11-rc1~1^2~2 X-Git-Url: http://pileus.org/git/?a=commitdiff_plain;h=c1e854e924f354657ea2ad08fd7b38aac81c59b1;p=~andy%2Flinux slob: Check for NULL pointer before calling ctor() While doing some code inspection, I noticed that the slob constructor method can be called with a NULL pointer. If memory is tight and slob fails to allocate with slob_alloc() or slob_new_pages() it still calls the ctor() method with a NULL pointer. Looking at the first ctor() method I found, I noticed that it can not handle a NULL pointer (I'm sure others probably can't either): static void sighand_ctor(void *data) { struct sighand_struct *sighand = data; spin_lock_init(&sighand->siglock); init_waitqueue_head(&sighand->signalfd_wqh); } The solution is to only call the ctor() method if allocation succeeded. Acked-by: Christoph Lameter Signed-off-by: Steven Rostedt Signed-off-by: Pekka Enberg --- diff --git a/mm/slob.c b/mm/slob.c index f729c46639f..3d73b3b8fb1 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -554,7 +554,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node) flags, node); } - if (c->ctor) + if (b && c->ctor) c->ctor(b); kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags);