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From: Chris Mason <chris.mason@oracle.com>
To: Jim Schutt <jaschut@sandia.gov>
Cc: Josef Bacik <josef@redhat.com>, linux-btrfs@vger.kernel.org
Subject: Re: kernel BUG at fs/btrfs/extent_io.c:3982!
Date: Wed, 11 Apr 2012 20:29:46 -0400	[thread overview]
Message-ID: <20120412002946.GF29506@shiny> (raw)
In-Reply-To: <4F85F9FB.5020007@sandia.gov>

On Wed, Apr 11, 2012 at 03:39:07PM -0600, Jim Schutt wrote:
> On 04/11/2012 02:28 PM, Josef Bacik wrote:
> >On Wed, Apr 11, 2012 at 02:24:30PM -0600, Jim Schutt wrote:
> >>On 04/11/2012 01:09 PM, Josef Bacik wrote:
> >>>On Tue, Apr 10, 2012 at 01:39:14PM -0600, Jim Schutt wrote:
> >>>>Hi,
> >>>>
> >>>>I hit this BUG today.
> >>>>
> >>>>I'm running 3.3.1 merged with the ceph and btrfs bits for 3.4,
> >>>>i.e. 3.3.1 +
> >>>>   commit bc3f116fec194 "Btrfs: update the checks for mixed block groups with big metadata blocks"
> >>>>   commit c666601a935b9 "rbd: move snap_rwsem to the device, rename to header_rwsem"
> >>>>
> >>>>The btrfs filesystem in question is backing a Ceph OSD under
> >>>>a heavy write load.
> >>>>
> >>>>Here's the bug:
> >>>>
> >>>
> >>>Can you give this a whirl and let me know how it goes?  If I'm right you should
> >>>see a warning pop up in your messages.  Thanks,
> >>
> >>OK, I've got my test running with your patch applied
> >>to my previous kernel.
> >>
> >>Do you expect your warning to only fire when my
> >>previous kernel would have BUGged?  I ask because I've
> >>only seen the BUG once, so it may be a low-probability
> >>occurrence.
> >>
> >>It seems like I should keep testing until I see either
> >>your new warning or the BUG, right?
> >>
> >
> >So hopefully you will see my WARN with no BUG, but yes keep running until you
> >see one or the other please ;).  Thanks,
> 
> Hmmm, the BUG won:
> 
> [ 6202.249041] ------------[ cut here ]------------
> [ 6202.253654] kernel BUG at fs/btrfs/extent_io.c:3989!

Since this is exactly the same call trace, we can assume ref count on
the buffer is correct.  I think it means we're racing on removing the
buffer from the radix tree.  I'm adding some diagnostics here to try and
grow the window a bit.

-chris

  reply	other threads:[~2012-04-12  0:29 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-10 19:39 kernel BUG at fs/btrfs/extent_io.c:3982! Jim Schutt
2012-04-10 20:24 ` Chris Mason
2012-04-10 20:32   ` Jim Schutt
2012-04-11 19:09 ` Josef Bacik
2012-04-11 20:24   ` Jim Schutt
2012-04-11 20:28     ` Josef Bacik
2012-04-11 21:39       ` Jim Schutt
2012-04-12  0:29         ` Chris Mason [this message]
2012-05-01 16:00     ` Josef Bacik
2012-05-01 16:41       ` Jim Schutt
2012-05-03 14:43         ` Jim Schutt
2012-05-03 14:53           ` Josef Bacik
2012-05-03 15:46             ` [EXTERNAL] " Jim Schutt
2012-05-03 15:53               ` Josef Bacik

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