From: Al Viro <viro@zeniv.linux.org.uk>
To: Mateusz Guzik <mjguzik@gmail.com>
Cc: Dave Chinner <david@fromorbit.com>,
syzbot <syzbot+e245f0516ee625aaa412@syzkaller.appspotmail.com>,
brauner@kernel.org, djwong@kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-xfs@vger.kernel.org, llvm@lists.linux.dev,
nathan@kernel.org, ndesaulniers@google.com,
syzkaller-bugs@googlegroups.com, trix@redhat.com
Subject: Re: [syzbot] [xfs?] INFO: task hung in __fdget_pos (4)
Date: Sun, 3 Sep 2023 19:01:26 +0100 [thread overview]
Message-ID: <20230903180126.GL3390869@ZenIV> (raw)
In-Reply-To: <20230903083357.75mq5l43gakuc2z7@f>
On Sun, Sep 03, 2023 at 10:33:57AM +0200, Mateusz Guzik wrote:
> On Sun, Sep 03, 2023 at 03:25:28PM +1000, Dave Chinner wrote:
> > On Sat, Sep 02, 2023 at 09:11:34PM -0700, syzbot wrote:
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit: b97d64c72259 Merge tag '6.6-rc-smb3-client-fixes-part1' of..
> > > git tree: upstream
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=14136d8fa80000
> > > kernel config: https://syzkaller.appspot.com/x/.config?x=958c1fdc38118172
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=e245f0516ee625aaa412
> > > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> > >
> > > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > Been happening for months, apparently, yet for some reason it now
> > thinks a locking hang in __fdget_pos() is an XFS issue?
> >
> > #syz set subsystems: fs
> >
>
> The report does not have info necessary to figure this out -- no
> backtrace for whichever thread which holds f_pos_lock. I clicked on a
> bunch of other reports and it is the same story.
>
> Can the kernel be configured to dump backtraces from *all* threads?
>
> If there is no feature like that I can hack it up.
<break>t
over serial console, or echo t >/proc/sysrq-trigger would do it...
"Locking hang in __fdget_pos()" would mean either something stuck inside
->read/->write/->read_iter/->write_iter/->llseek instance, making
any further syscalls in that bunch on the same open file to block,
or a lost fdput_pos() somewhere; AFAICS, we don't have anything of
the latter variety, but the former is too wide to tell anything
useful.
next prev parent reply other threads:[~2023-09-03 18:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-03 4:11 [syzbot] [xfs?] INFO: task hung in __fdget_pos (4) syzbot
2023-09-03 5:25 ` Dave Chinner
2023-09-03 8:33 ` Mateusz Guzik
2023-09-03 18:01 ` Al Viro [this message]
2023-09-03 18:57 ` Mateusz Guzik
2023-09-03 19:51 ` Al Viro
2023-09-03 20:04 ` Mateusz Guzik
2023-09-06 17:53 ` Aleksandr Nogikh
2023-09-03 22:27 ` Dave Chinner
2023-09-03 22:47 ` Mateusz Guzik
2023-09-03 23:09 ` Dave Chinner
2023-09-04 8:11 ` Christian Brauner
2023-09-04 8:23 ` Christian Brauner
2023-09-04 8:55 ` Dave Chinner
2023-09-03 23:13 ` Al Viro
2023-09-04 1:45 ` Dave Chinner
2023-09-04 3:02 ` Al Viro
2023-09-04 3:26 ` Theodore Ts'o
2023-09-04 6:09 ` Mateusz Guzik
2023-11-30 16:58 ` [syzbot] [fs] " syzbot
2024-09-21 5:58 ` syzbot
2024-10-31 13:38 ` syzbot
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