From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Greear Subject: Re: BUG: soft lockup detected on CPU#0! (2.6.18.2 plus hacks) Date: Mon, 08 Jan 2007 08:57:10 -0800 Message-ID: <45A277E6.6000904@candelatech.com> References: <20070104.123333.91315611.davem@davemloft.net> <459EB627.5040606@candelatech.com> <20070108065346.GA1665@ff.dom.local> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: David Miller , herbert@gondor.apana.org.au, dlstevens@us.ibm.com, netdev@vger.kernel.org Return-path: Received: from ns2.lanforge.com ([66.165.47.211]:37297 "EHLO ns2.lanforge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750913AbXAHQzz (ORCPT ); Mon, 8 Jan 2007 11:55:55 -0500 To: Jarek Poplawski In-Reply-To: <20070108065346.GA1665@ff.dom.local> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Jarek Poplawski wrote: > On Fri, Jan 05, 2007 at 12:33:43PM -0800, Ben Greear wrote: > ... > >> So, I do believe this was the problem we were hitting, and it seems fixed. >> > > Congratulations! > > But I can see one strange thing in vlan.c: > > /* Must be invoked with RCU read lock (no preempt) */ > static struct vlan_group *__vlan_find_group(int real_dev_ifindex) > ... > * Must be invoked with RCU read lock (no preempt) > */ > struct net_device *__find_vlan_dev(struct net_device *real_dev, > ... > > But later in this file no sign of disabling preemption > for these calls and for hlist_add_head_rcu and hlist_del_rcu. > > I can't imagine how this works? > Perhaps...I didn't RCU-ify VLANs, but I can take a look. For the record, the soft lockup was using MAC-VLANs, not 802.1Q VLANs, so it wouldn't have been affected by bugs in VLANs one way or the other. Ben > Jarek P. > -- Ben Greear Candela Technologies Inc http://www.candelatech.com