linux-kernel - Re: [syzbot] [reiserfs?] possible deadlock in super

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Thu, 28 Dec 2023 11:50:32 +0100
From: Christian Brauner <brauner@...nel.org>
To: syzbot <syzbot+062317ea1d0a6d5e29e7@...kaller.appspotmail.com>
Cc: axboe@...nel.dk, chao@...nel.org, christian@...uner.io,
	daniel.vetter@...ll.ch, hch@....de, hdanton@...a.com, jack@...e.cz,
	jaegeuk@...nel.org, jinpu.wang@...os.com,
	linux-f2fs-devel@...ts.sourceforge.net,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
	mairacanal@...eup.net, mcanal@...lia.com,
	reiserfs-devel@...r.kernel.org, syzkaller-bugs@...glegroups.com,
	terrelln@...com, willy@...radead.org, yukuai3@...wei.com
Subject: Re: [syzbot] [reiserfs?] possible deadlock in super_lock

On Sun, Dec 24, 2023 at 08:40:05AM -0800, syzbot wrote:
> syzbot suspects this issue was fixed by commit:
> 
> commit fd1464105cb37a3b50a72c1d2902e97a71950af8
> Author: Jan Kara <jack@...e.cz>
> Date:   Wed Oct 18 15:29:24 2023 +0000
> 
>     fs: Avoid grabbing sb->s_umount under bdev->bd_holder_lock
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=14639595e80000
> start commit:   2cf0f7156238 Merge tag 'nfs-for-6.6-2' of git://git.linux-..
> git tree:       upstream
> kernel config:  https://syzkaller.appspot.com/x/.config?x=710dc49bece494df
> dashboard link: https://syzkaller.appspot.com/bug?extid=062317ea1d0a6d5e29e7
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=107e9518680000
> 
> If the result looks correct, please mark the issue as fixed by replying with:
> 
> #syz fix: fs: Avoid grabbing sb->s_umount under bdev->bd_holder_lock
> 
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection

Fwiw, this was always a false-positive. But we also reworked the locking
that even the false-positive cannot be triggered anymore. So yay!