From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030495AbXDPMEP (ORCPT ); Mon, 16 Apr 2007 08:04:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030501AbXDPMEP (ORCPT ); Mon, 16 Apr 2007 08:04:15 -0400 Received: from mailhub.sw.ru ([195.214.233.200]:46381 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030495AbXDPMEO (ORCPT ); Mon, 16 Apr 2007 08:04:14 -0400 Message-ID: <46236739.5000409@sw.ru> Date: Mon, 16 Apr 2007 16:08:25 +0400 From: Pavel Emelianov User-Agent: Thunderbird 1.5 (X11/20060317) MIME-Version: 1.0 To: Andrew Morton , Linux Kernel Mailing List , devel@openvz.org Subject: [PATCH] Set a separate lockdep class for neighbour table's proxy_queue Content-Type: multipart/mixed; boundary="------------000704030900030605080103" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------000704030900030605080103 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Otherwise the following calltrace will lead to a wrong lockdep warning: neigh_proxy_process() `- lock(neigh_table->proxy_queue.lock); arp_redo /* via tbl->proxy_redo */ arp_process neigh_event_ns neigh_update skb_queue_purge `- lock(neighbor->arp_queue.lock); This is not a deadlock actually, as neighbor table's proxy_queue and the neighbor's arp_queue are different queues. Lockdep thinks there is a deadlock as both queues are initialized with skb_queue_head_init() and thus have a common class. --------------000704030900030605080103 Content-Type: text/plain; name="diff-set-lockdep-class-for-neighbour-table-skb-list" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="diff-set-lockdep-class-for-neighbour-table-skb-list" --- a/include/linux/skbuff.h 2007-04-09 22:52:27.000000000 +0400 +++ b/include/linux/skbuff.h 2007-04-09 22:52:32.000000000 +0400 @@ -628,6 +628,13 @@ static inline void skb_queue_head_init(s list->qlen = 0; } +static inline void skb_queue_head_init_class(struct sk_buff_head *list, + struct lock_class_key *class) +{ + skb_queue_head_init(list); + lockdep_set_class(&list->lock, class); +} + /* * Insert an sk_buff at the start of a list. * --- a/net/core/neighbour.c 2007-04-09 22:52:28.000000000 +0400 +++ b/net/core/neighbour.c 2007-04-09 22:53:01.000000000 +0400 @@ -1327,6 +1327,8 @@ void neigh_parms_destroy(struct neigh_pa kfree(parms); } +static struct lock_class_key neigh_table_proxy_queue_class; + void neigh_table_init_no_netlink(struct neigh_table *tbl) { unsigned long now = jiffies; @@ -1379,7 +1381,8 @@ void neigh_table_init_no_netlink(struct init_timer(&tbl->proxy_timer); tbl->proxy_timer.data = (unsigned long)tbl; tbl->proxy_timer.function = neigh_proxy_process; - skb_queue_head_init(&tbl->proxy_queue); + skb_queue_head_init_class(&tbl->proxy_queue, + &neigh_table_proxy_queue_class); tbl->last_flush = now; tbl->last_rand = now + tbl->parms.reachable_time * 20; --------------000704030900030605080103--