linux-xfs.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Dave Chinner <david@fromorbit.com>
To: syzbot <syzbot+4bb1622c9a583bb6f9f2@syzkaller.appspotmail.com>
Cc: a@unstable.cc, axboe@kernel.dk, b.a.t.m.a.n@lists.open-mesh.org,
	davem@davemloft.net, djwong@kernel.org, josef@toxicpanda.com,
	linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org,
	mareklindner@neomailbox.ch, mchristi@redhat.com,
	netdev@vger.kernel.org, sw@simonwunderlich.de,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] INFO: task hung in __xfs_buf_submit (2)
Date: Thu, 26 Aug 2021 07:45:34 +1000	[thread overview]
Message-ID: <20210825214534.GM3657114@dread.disaster.area> (raw)
In-Reply-To: <0000000000002fc21105ca657edf@google.com>

On Wed, Aug 25, 2021 at 10:22:21AM -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    6e764bcd1cf7 Merge tag 'for-linus' of git://git.kernel.org..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=10504885300000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=2fd902af77ff1e56
> dashboard link: https://syzkaller.appspot.com/bug?extid=4bb1622c9a583bb6f9f2
> compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.1
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14427606300000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=149b3cce300000
> 
> The issue was bisected to:
> 
> commit 887e975c4172d0d5670c39ead2f18ba1e4ec8133
> Author: Mike Christie <mchristi@redhat.com>
> Date:   Tue Aug 13 16:39:51 2019 +0000
> 
>     nbd: add missing config put
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11980ad5300000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=13980ad5300000
> console output: https://syzkaller.appspot.com/x/log.txt?x=15980ad5300000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+4bb1622c9a583bb6f9f2@syzkaller.appspotmail.com
> Fixes: 887e975c4172 ("nbd: add missing config put")

XFS is waiting on IO completion to be signalled from the block
device, and the bisect points to commit fixing a problem with a
block device processing IO timeout errors.

IOWs, the above commit is probably exposing a latent bug in the
commit that changes all the error handling in nbd to fix completion
races in IO completion. The commit message for 8f3ea35929a0 ("nbd:
handle unexpected replies better") also makes mention of races with
timeout errors, and the above commit is touching the timeout error
handling.

Josef, this one looks like it is yours...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

      reply	other threads:[~2021-08-25 21:45 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-25 17:22 syzbot
2021-08-25 21:45 ` Dave Chinner [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210825214534.GM3657114@dread.disaster.area \
    --to=david@fromorbit.com \
    --cc=a@unstable.cc \
    --cc=axboe@kernel.dk \
    --cc=b.a.t.m.a.n@lists.open-mesh.org \
    --cc=davem@davemloft.net \
    --cc=djwong@kernel.org \
    --cc=josef@toxicpanda.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=mareklindner@neomailbox.ch \
    --cc=mchristi@redhat.com \
    --cc=netdev@vger.kernel.org \
    --cc=sw@simonwunderlich.de \
    --cc=syzbot+4bb1622c9a583bb6f9f2@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    --subject='Re: [syzbot] INFO: task hung in __xfs_buf_submit (2)' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).