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From: Amir Goldstein <amir73il@gmail.com>
Date: Fri, 5 Apr 2024 18:08:13 +0300
Message-ID: <CAOQ4uxhm5m9CvX0y2RcJGuP=vryZLp9M+tS6vH1o_9BGUqxrvg@mail.gmail.com>
Subject: Re: [syzbot] [kernfs?] possible deadlock in kernfs_fop_llseek
To: syzbot <syzbot+9a5b0ced8b1bfb238b56@syzkaller.appspotmail.com>
Cc: gregkh@linuxfoundation.org, linux-fsdevel@vger.kernel.org, 
	linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, tj@kernel.org, 
	valesini@yandex-team.ru, Christoph Hellwig <hch@lst.de>, 
	Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>, Miklos Szeredi <miklos@szeredi.hu>, 
	Al Viro <viro@zeniv.linux.org.uk>
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On Thu, Apr 4, 2024 at 9:54=E2=80=AFAM Amir Goldstein <amir73il@gmail.com> =
wrote:
>
> On Thu, Apr 4, 2024 at 2:51=E2=80=AFAM syzbot
> <syzbot+9a5b0ced8b1bfb238b56@syzkaller.appspotmail.com> wrote:
> >
> > syzbot has bisected this issue to:
> >
> > commit 0fedefd4c4e33dd24f726b13b5d7c143e2b483be
> > Author: Valentine Sinitsyn <valesini@yandex-team.ru>
> > Date:   Mon Sep 25 08:40:12 2023 +0000
> >
> >     kernfs: sysfs: support custom llseek method for sysfs entries
> >
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=3D17cb5e03=
180000
> > start commit:   fe46a7dd189e Merge tag 'sound-6.9-rc1' of git://git.ker=
nel..
> > git tree:       upstream
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=3D142b5e03=
180000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=3D102b5e03180=
000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=3D4d90a36f0ca=
b495a
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3D9a5b0ced8b1bf=
b238b56
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D17f1d93d1=
80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D15c38139180=
000
> >
> > Reported-by: syzbot+9a5b0ced8b1bfb238b56@syzkaller.appspotmail.com
> > Fixes: 0fedefd4c4e3 ("kernfs: sysfs: support custom llseek method for s=
ysfs entries")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bise=
ction
> >
>

Let's test Al's solution.

#syz test: https://github.com/amir73il/linux/ vfs-fixes

Thanks,
Amir.