From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754201AbaBDMgm (ORCPT ); Tue, 4 Feb 2014 07:36:42 -0500 Received: from relay.parallels.com ([195.214.232.42]:42044 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751513AbaBDMgk (ORCPT ); Tue, 4 Feb 2014 07:36:40 -0500 From: Vladimir Davydov To: CC: , , , Subject: [PATCH] slub: fix false-positive lockdep warning in free_partial() Date: Tue, 4 Feb 2014 16:36:37 +0400 Message-ID: <1391517397-6142-1-git-send-email-vdavydov@parallels.com> X-Mailer: git-send-email 1.7.10.4 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.30.16.96] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit c65c1877bd68 ("slub: use lockdep_assert_held") requires remove_partial() to be called with n->list_lock held, but free_partial() called from kmem_cache_close() on cache destruction does not follow this rule, leading to a warning: WARNING: CPU: 0 PID: 2787 at mm/slub.c:1536 __kmem_cache_shutdown+0x1b2/0x1f0() Modules linked in: CPU: 0 PID: 2787 Comm: modprobe Tainted: G W 3.14.0-rc1-mm1+ #1 Hardware name: 0000000000000600 ffff88003ae1dde8 ffffffff816d9583 0000000000000600 0000000000000000 ffff88003ae1de28 ffffffff8107c107 0000000000000000 ffff880037ab2b00 ffff88007c240d30 ffffea0001ee5280 ffffea0001ee52a0 Call Trace: [] dump_stack+0x51/0x6e [] warn_slowpath_common+0x87/0xb0 [] warn_slowpath_null+0x15/0x20 [] __kmem_cache_shutdown+0x1b2/0x1f0 [] kmem_cache_destroy+0x43/0xf0 [] xfs_destroy_zones+0x103/0x110 [xfs] [] exit_xfs_fs+0x38/0x4e4 [xfs] [] SyS_delete_module+0x19a/0x1f0 [] ? retint_swapgs+0x13/0x1b [] ? trace_hardirqs_on_caller+0x105/0x1d0 [] ? trace_hardirqs_on_thunk+0x3a/0x3f [] system_call_fastpath+0x16/0x1b Although this cannot actually result in a race, because on cache destruction there should not be any concurrent frees or allocations from the cache, let's add spin_lock/unlock to free_partial() just to keep lockdep happy. Signed-off-by: Vladimir Davydov --- mm/slub.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index 0eeea85034c8..b1054568a76e 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3191,6 +3191,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) { struct page *page, *h; + spin_lock_irq(&n->list_lock); list_for_each_entry_safe(page, h, &n->partial, lru) { if (!page->inuse) { remove_partial(n, page); @@ -3200,6 +3201,7 @@ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) "Objects remaining in %s on kmem_cache_close()"); } } + spin_unlock_irq(&n->list_lock); } /* -- 1.7.10.4