From 255d0884f5635122adb23866b242b4ca112f4bc8 Mon Sep 17 00:00:00 2001
From: David Rientjes <rientjes@google.com>
Date: Mon, 10 Feb 2014 14:25:39 -0800
Subject: [PATCH] mm/slub.c: list_lock may not be held in some circumstances
Commit c65c1877bd68 ("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>
---
mm/slub.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index 7e3e0458bce4..3d3a8a7a0f8c 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -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);
}
--
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