From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-btrfs-owner@vger.kernel.org>
Received: from mx2.fusionio.com ([66.114.96.31]:55381 "EHLO mx2.fusionio.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1750906Ab2GFPTF (ORCPT <rfc822;linux-btrfs@vger.kernel.org>);
	Fri, 6 Jul 2012 11:19:05 -0400
Date: Fri, 6 Jul 2012 11:19:02 -0400
From: Chris Mason <chris.mason@fusionio.com>
To: Jan Schmidt <list.btrfs@jan-o-sch.net>
CC: "Chris L. Mason" <clmason@fusionio.com>,
        "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: btrfs GPF in read_extent_buffer() while scrubbing with kernel
 3.4.2
Message-ID: <20120706151902.GO7159@shiny>
References: <4FF42876.8010309@jan-o-sch.net>
 <20120704160340.GA9770@sli.dy.fi>
 <4FF47168.9010405@jan-o-sch.net>
 <20120704202452.GA8996@sli.dy.fi>
 <4FF5998D.8020205@jan-o-sch.net>
 <20120705234739.GA9736@sli.dy.fi>
 <4FF6C12A.10305@jan-o-sch.net>
 <20120706143350.GA10427@sli.dy.fi>
 <20120706144030.GL7159@shiny>
 <4FF6FE0A.2090204@jan-o-sch.net>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
In-Reply-To: <4FF6FE0A.2090204@jan-o-sch.net>
Sender: linux-btrfs-owner@vger.kernel.org
List-ID: <linux-btrfs.vger.kernel.org>

On Fri, Jul 06, 2012 at 09:02:34AM -0600, Jan Schmidt wrote:
> On Fri, July 06, 2012 at 16:40 (+0200), Chris Mason wrote:
> > On Fri, Jul 06, 2012 at 08:33:51AM -0600, Sami Liedes wrote:
> >> On Fri, Jul 06, 2012 at 12:42:50PM +0200, Jan Schmidt wrote:
> >>> I've no good idea at the moment how to go on. It might help to get a feeling if
> >>> it's shifting around at least a little bit or really constant in the timing of
> >>> occurrence. So can you please apply the next patch on top of the other two and
> >>> give it some more failure tries? The "checksum mismatch [1234]" line will be of
> >>> most interest. I'm also curious what the additional debug variables will say in
> >>> the extended version of the very first printk. You can leave out the stack
> >>> traces if you like, they won't matter much anyway.
> >>
> >> Ok. Also turned on CONFIG_DEBUG_PAGEALLOC and CONFIG_SLUB_DEBUG_ON as
> >> suggested by Chris Mason.
> >>
> >> With those and the latest patch, there's an oops already at boot. I
> >> don't have netconsole yet at that point, but here's the important
> >> parts (sure I can capture it fully if you need).
> >>
> >> By the way, something seems to be untabifying your patches. I don't
> >> know if it's on my side or yours, but at least some other patches I
> >> receive via linux-btrfs contain tabs. Doing a M-x tabify in emacs
> >> mostly makes them apply cleanly for me.
> >>
> >> 	Sami
> >>
> >>
> >> ------------------------------------------------------------
> >> btrfs: disk space caching is enabled
> >> BUG: unable to handle kernel NULL pointer dereference at 0000000000000150
> >> IP: [<ffffffffa0223568>] check_node+0x138/0x250 [btrfs]
> > 
> > This isn't from any of the new debugging.  Can you please try it on an
> > unpatched kernel?
> 
> You're confusing that with check_leaf. I added check_node along the way, see my
> mail from Thu, July 05, 2012 at 15:41 (+0200). I'd really like to add something
> similar for the 3.6 series.
> 
> Checking for the null pointer dereference.

Sorry, I wasn't clear.  I meant it wasn't from slab debug or
DEBUG_PAGEALLOC, so it must be new in your patches ;)

-chris