Commit 66c4c35c authored Jan 17, 2012 by Christoph Lameter Committed by Pekka Enberg Feb 06, 2012

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: <stable@vger.kernel.org>	# 3.3+
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>

parent 0ad9500e

mm/slub.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -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);

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