From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262076AbULVXMP (ORCPT ); Wed, 22 Dec 2004 18:12:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262078AbULVXMP (ORCPT ); Wed, 22 Dec 2004 18:12:15 -0500 Received: from omx2-ext.sgi.com ([192.48.171.19]:4530 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S262076AbULVXMI (ORCPT ); Wed, 22 Dec 2004 18:12:08 -0500 Date: Thu, 23 Dec 2004 10:11:43 +1100 From: Nathan Scott To: Joerg Sommrey , Christoph Hellwig Cc: Linux kernel mailing list Subject: Re: Oops on 2.6.9-ac16: xfs, dm and md may be involved Message-ID: <20041223101143.A702917@wobbly.melbourne.sgi.com> References: <20041221185754.GA28356@sommrey.de> <20041222182606.GA14733@infradead.org> <20041222195203.GA24857@sommrey.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20041222195203.GA24857@sommrey.de>; from jo@sommrey.de on Wed, Dec 22, 2004 at 08:52:03PM +0100 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 22, 2004 at 08:52:03PM +0100, Joerg Sommrey wrote: > On Wed, Dec 22, 2004 at 06:26:06PM +0000, Christoph Hellwig wrote: > > On Tue, Dec 21, 2004 at 07:57:54PM +0100, Joerg Sommrey wrote: > > > Hello, > > > > > > last night my box died with a kernel oops. There was a backup > > > running at that time. The setup: > > > - 2 SATA disks + 1 SCSI disk > > > - SATA partitions build up md-raid-arrays (level 0 and 1) > > > - md-raid-devices and SCSI partitions are physical volumes for dm > > > - dm logical volumes are used for xfs filesystems > > > - backup is done on dm-snapshots of those filesystems > > > > Given the strange backtrace and this enormous stack of drivers I bet > > you're seeing a stack overflow. Hmm, I'm not real sure of that Christoph - this was inside a kernel thread (xfsbufd) where there is almost nothing on the stack at the point we dove into driver land. Looked like a genuine bug to me. There were plenty of calls on the trace, but I think several of those were badly guessed by the stack dump code. And a couple of registers having a memory poison pattern looked a bit suspect. > Does this mean that this kind of stuff just doesn't work? I was running > a 4K-stack kernel with this "stack of drivers" for quiet some time without > problems. The problems started around 2.6.9-pre-something. Converting > to 8K-stacks didn't help. Is this only xfs related? Certainly wasn't XFS using stack in the initial oops, perhaps the lower layers, but I'm a bit sceptical. Almost certainly this is a device mapper snapshot problem, the DM folks should be able to analyse it further. cheers. -- Nathan