Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753414Ab1DUHQq (ORCPT ); Thu, 21 Apr 2011 03:16:46 -0400 Received: from cantor2.suse.de ([195.135.220.15]:53363 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753006Ab1DUHQp (ORCPT ); Thu, 21 Apr 2011 03:16:45 -0400 Date: Thu, 21 Apr 2011 09:16:42 +0200 From: Michal Hocko To: Jens Axboe Cc: Linus Torvalds , LKML Subject: Re: 2.6.39-rc4 BUG: unable to handle kernel NULL pointer dereference at 0000000c IP: cfq_insert_request+0x1d/0x3f5 Message-ID: <20110421071642.GA3556@tiehlicka.suse.cz> References: <20110420125824.GA3507@tiehlicka.suse.cz> <4DAEDBEB.7060904@fusionio.com> <20110420132903.GA13554@tiehlicka.suse.cz> <4DAF18DF.9080205@fusionio.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4DAF18DF.9080205@fusionio.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1512 Lines: 40 On Wed 20-04-11 19:33:19, Jens Axboe wrote: > On 2011-04-20 15:29, Michal Hocko wrote: > > On Wed 20-04-11 15:13:15, Jens Axboe wrote: > >> On 2011-04-20 14:58, Michal Hocko wrote: [...] > >>> [ 31.207888] Oops: 0000 [#1] PREEMPT [ 31.208186] last sysfs file: /sys/devices/pci0000:00/0000:00:1f.2/host0/target0:0:0/0:0:0:0/block/sda/queue/scheduler > >> > >> Ahh hang on, this may be a good clue. Does your boot scripts change the > >> IO scheduler? > > > > Good one... > > Yes, I have: > > echo deadline > /sys/block/sda/queue/scheduler > > in /etc/rc.local > > > > I am able to boot after I remove it. This is the first time I have seen > > "last sysfs file" being useful. > > Still want me to test the patch from the other email? > > Is this a new addition to your system? IOW, how certain are you that > this is a regression that occured between rc3 and rc4? No, I am setting the scheduler this way for quite some time. If I use it rc4 explodes while rc3 boots just fine. I am wondering, can this be a timing issue? I am able to set the scheduler after system settles down after boot and kde starts. I am going to bisect, let's see if I can find anything. -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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/