| From 66c4c35c6bc5a1a452b024cf0364635b28fd94e4 Mon Sep 17 00:00:00 2001 |
| From: Christoph Lameter <cl@linux.com> |
| Date: Tue, 17 Jan 2012 09:27:31 -0600 |
| Subject: slub: Do not hold slub_lock when calling sysfs_slab_add() |
| |
| From: Christoph Lameter <cl@linux.com> |
| |
| commit 66c4c35c6bc5a1a452b024cf0364635b28fd94e4 upstream. |
| |
| 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. |
| |
| Reported-by: Sasha Levin <levinsasha928@gmail.com> |
| Acked-by: Eric Dumazet <eric.dumazet@gmail.com> |
| Signed-off-by: Christoph Lameter <cl@linux.com> |
| Signed-off-by: Pekka Enberg <penberg@kernel.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| mm/slub.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| --- a/mm/slub.c |
| +++ b/mm/slub.c |
| @@ -3911,13 +3911,14 @@ struct kmem_cache *kmem_cache_create(con |
| 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); |