| | Date | Fri, 30 Mar 2012 12:58:54 -0700 | | From | Greg KH <> | | Subject | [ 092/108] slub: Do not hold slub_lock when calling sysfs_slab_add() |
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3.0-stable review patch. If anyone has any objections, please let me know.
------------------ 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 @@ -3439,13 +3439,14 @@ 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);
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