From c1e854e924f354657ea2ad08fd7b38aac81c59b1 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 17 Jan 2013 12:13:46 -0500 Subject: [PATCH] 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 --- mm/slob.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/slob.c b/mm/slob.c index f729c46..3d73b3b 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); -- 2.7.4