Commit 255d0884 authored Feb 10, 2014 by David Rientjes Committed by Linus Torvalds Feb 10, 2014

mm/slub.c: list_lock may not be held in some circumstances



Commit c65c1877 ("slub: use lockdep_assert_held") incorrectly
required that add_full() and remove_full() hold n->list_lock.  The lock
is only taken when kmem_cache_debug(s), since that's the only time it
actually does anything.

Require that the lock only be taken under such a condition.

Reported-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent bd180b4e

mm/slub.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -1004,21 +1004,19 @@ static inline void slab_free_hook(struct kmem_cache s, void x)
		static void add_full(struct kmem_cache *s,
		struct kmem_cache_node n, struct page page)
		{
		lockdep_assert_held(&n->list_lock);

		if (!(s->flags & SLAB_STORE_USER))
		return;

		lockdep_assert_held(&n->list_lock);
		list_add(&page->lru, &n->full);
		}

		static void remove_full(struct kmem_cache s, struct kmem_cache_node n, struct page *page)
		{
		lockdep_assert_held(&n->list_lock);

		if (!(s->flags & SLAB_STORE_USER))
		return;

		lockdep_assert_held(&n->list_lock);
		list_del(&page->lru);
		}