Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423651Ab2KOJk6 (ORCPT ); Thu, 15 Nov 2012 04:40:58 -0500 Received: from cantor2.suse.de ([195.135.220.15]:59561 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423637Ab2KOJkv (ORCPT ); Thu, 15 Nov 2012 04:40:51 -0500 Date: Thu, 15 Nov 2012 10:40:46 +0100 From: Jan Kara To: Michael Wang Cc: =?utf-8?B?UGF3ZcWC?= Sikora , linux-kernel@vger.kernel.org, stable@vger.kernel.org, torvalds@linux-foundation.org, arekm@pld-linux.org, baggins@pld-linux.org, Alexander Viro , Fengguang Wu , Johannes Weiner , jack@suse.cz, linux-mm@kvack.org Subject: Re: [3.6.6] panic on reboot / khungtaskd blocked? (WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule) Message-ID: <20121115094046.GD1394@quack.suse.cz> References: <56378024.A3Kec8xZj0@pawels> <2413953.H7iie8v1th@pawels> <50A302C9.2060800@linux.vnet.ibm.com> <1984533.1jAeFKDqSR@localhost> <50A44854.6040905@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <50A44854.6040905@linux.vnet.ibm.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3379 Lines: 75 On Thu 15-11-12 09:41:40, Michael Wang wrote: > On 11/15/2012 05:10 AM, Paweł Sikora wrote: > > On Wednesday 14 of November 2012 10:32:41 Michael Wang wrote: > >> On 11/13/2012 05:40 PM, Paweł Sikora wrote: > >>> On Monday 12 of November 2012 13:33:39 Paweł Sikora wrote: > >>>> On Monday 12 of November 2012 11:22:47 Paweł Sikora wrote: > >>>>> On Monday 12 of November 2012 15:40:31 Michael Wang wrote: > >>>>>> On 11/12/2012 03:16 PM, Paweł Sikora wrote: > >>>>>>> On Monday 12 of November 2012 11:04:12 Michael Wang wrote: > >>>>>>>> On 11/09/2012 09:48 PM, Paweł Sikora wrote: > >>>>>>>>> Hi, > >>>>>>>>> > >>>>>>>>> during playing with new ups i've caught an nice oops on reboot: > >>>>>>>>> > >>>>>>>>> http://imgbin.org/index.php?page=image&id=10253 > >>>>>>>>> > >>>>>>>>> probably the upstream is also affected. > >>>>>>>> > >>>>>>>> Hi, Paweł > >>>>>>>> > >>>>>>>> Are you using a clean 3.6.6 without any modify? > >>>>>>> > >>>>>>> yes, pure 3.6.6 form git tree with modular config. > >>>>>>> > >>>>>>>> Looks like some threads has set itself to be UNINTERRUPTIBLE with out > >>>>>>>> any design on switch itself back later(or the time is too long), are you > >>>>>>>> accidentally using some bad designed module? > >>>>>>> > >>>>>>> hmm, hard to say. mostly all modules are loaded automatically by kernel. > >>>>>> > >>>>>> Could you please provide the whole dmesg in text? your picture lost the > >>>>>> print info of the hung task. > >>>>> > >>>>> i've grabbed the console via rs232 but there's no more info (see attached txt). > >>>> > >>>> hmm, i have one observation. > >>>> > >>>> during rc.shutdown there're messages on console like this: Cannot stat file /proc/$pid/fd/1: Connection timed out > >>>> afaics this file descriptor points to vnc log file on a remote machine, e.g.: > >>>> > >>>> # ps aux|grep xfwm4 > >>>> eda 1748 0.0 0.0 320220 11224 ? S 13:08 0:00 xfwm4 > >>>> > >>>> # readlink -m /proc/1748/fd/1 > >>>> /remote/dragon/ahome/eda/.vnc/odra:11.log > >>>> > >>>> # mount|grep ahome > >>>> dragon:/home/users/ on /remote/dragon/ahome type nfs (rw,relatime,vers=3,rsize=262144,wsize=262144,namlen=255,soft,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=10.0.2.121,mountvers=3,mountport=45251,mountproto=udp,local_lock=none,addr=10.0.2.121) > >>>> > >>>> > >>>> so, probably during `killall5 -TERM/-KILL` on shutdown stage something sometimes go wrong > >>>> and these processes (xfce4/vncserver) survive the signal and hang on the nfs i/o. > >>>> > >>> > >>> ok, now i have full sysrq+w backtraces from shutdown process. i hope i'll help you. > >> > >> This can only tell us what's the task in UNINTERRUPTABLE state, but with > >> out time info, we can't find out which one is the hung task... > > So it's blocked on __lock_page() for too long? > Add more experts in mm aspect to cc. It's really NFS related. E.g. in trace https://lkml.org/lkml/2012/11/14/657 we are waiting on PageWriteback bit in fact - i.e. we have submitted data to the NFS server and are waiting for its response that the data was written. Honza -- Jan Kara SUSE Labs, CR -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/