From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757974Ab3JKN33 (ORCPT ); Fri, 11 Oct 2013 09:29:29 -0400 Received: from mail-pb0-f48.google.com ([209.85.160.48]:38814 "EHLO mail-pb0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753552Ab3JKN31 (ORCPT ); Fri, 11 Oct 2013 09:29:27 -0400 Message-ID: <5257FD34.2060406@gmail.com> Date: Fri, 11 Oct 2013 07:29:24 -0600 From: David Ahern User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 MIME-Version: 1.0 To: Ian Kent CC: autofs@vger.kernel.org, viro@ZenIV.linux.org.uk, linux-kernel@vger.kernel.org Subject: Re: NULL pointer dereference in autofs4_expire_wait References: <525736C7.9080400@gmail.com> <1381457199.2631.3.camel@perseus.fritz.box> <1381485327.2631.18.camel@perseus.fritz.box> In-Reply-To: <1381485327.2631.18.camel@perseus.fritz.box> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/11/13 3:55 AM, Ian Kent wrote: > On Fri, 2013-10-11 at 10:06 +0800, Ian Kent wrote: >> On Thu, 2013-10-10 at 17:22 -0600, David Ahern wrote: >>> Running 3.12-rc3 just hit BUG in autofs4_expire_wait >> >> It doesn't look like this could be due to Al's change to the locking in >> autos4_wait() and that the only change to autofs that I'm aware of. >> >> Could you do a bisect please? > > Of course that assumes it's repeatable. > Is it? > > Can you provide any information about the environment and activity that > was happening at the time of the BUG()? The system was up and running for 9 days before hitting the BUG. After that with 3 cpus on softlockup I had to do a reboot (forced). After the reboot I continued the workload again without a repeat incident (yet), so I am not sure bisect is going to be possible. This is a corporate environment where practically everything is in an automount. Specific to this problem I was repeatedly building a workspace in one window, using cscope in another and checking code against a different workspace in a third -- all 3 of those were different automounts and different NAS servers. From objdump on vmlinux the line in question is fs/autofs4/expire.c:465 if (ino->flags & AUTOFS_INF_EXPIRING) { I will be continuing the sequence above today (working through compile problems for on OS port). I will bump the kernel to top of tree and see if it repeats. David