From 66c4c35c6bc5a1a452b024cf0364635b28fd94e4 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Tue, 17 Jan 2012 09:27:31 -0600 Subject: slub: Do not hold slub_lock when calling sysfs_slab_add() sysfs_slab_add() calls various sysfs functions that actually may end up in userspace doing all sorts of things. Release the slub_lock after adding the kmem_cache structure to the list. At that point the address of the kmem_cache is not known so we are guaranteed exlusive access to the following modifications to the kmem_cache structure. If the sysfs_slab_add fails then reacquire the slub_lock to remove the kmem_cache structure from the list. Cc: # 3.3+ Reported-by: Sasha Levin Acked-by: Eric Dumazet Signed-off-by: Christoph Lameter Signed-off-by: Pekka Enberg --- mm/slub.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 5b915e8..bc7a8af 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3937,13 +3937,14 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, if (kmem_cache_open(s, n, size, align, flags, ctor)) { list_add(&s->list, &slab_caches); + up_write(&slub_lock); if (sysfs_slab_add(s)) { + down_write(&slub_lock); list_del(&s->list); kfree(n); kfree(s); goto err; } - up_write(&slub_lock); return s; } kfree(n); -- cgit v1.1