linux-kernel - Re: bio linked list corruption.

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]

Message-ID: <CAOMGZ=G_wM13ikKt7cTUt1gppsf4TAzFwg2kybUYMvEuzJyj2w@mail.gmail.com>
Date:   Mon, 5 Dec 2016 21:10:57 +0100
From:   Vegard Nossum <vegard.nossum@...il.com>
To:     Linus Torvalds <torvalds@...ux-foundation.org>
Cc:     Dave Jones <davej@...emonkey.org.uk>, Chris Mason <clm@...com>,
        Jens Axboe <axboe@...com>,
        Andy Lutomirski <luto@...capital.net>,
        Andy Lutomirski <luto@...nel.org>,
        Al Viro <viro@...iv.linux.org.uk>, Josef Bacik <jbacik@...com>,
        David Sterba <dsterba@...e.com>,
        linux-btrfs <linux-btrfs@...r.kernel.org>,
        Linux Kernel <linux-kernel@...r.kernel.org>,
        Dave Chinner <david@...morbit.com>
Subject: Re: bio linked list corruption.

On 5 December 2016 at 20:11, Vegard Nossum <vegard.nossum@...il.com> wrote:
> On 5 December 2016 at 18:55, Linus Torvalds
> <torvalds@...ux-foundation.org> wrote:
>> On Mon, Dec 5, 2016 at 9:09 AM, Vegard Nossum <vegard.nossum@...il.com> wrote:
>> Since you apparently can recreate this fairly easily, how about trying
>> this stupid patch?
>>
>> NOTE! This is entirely untested. I may have screwed this up entirely.
>> You get the idea, though - just remove the wait queue head from the
>> list - the list entries stay around, but nothing points to the stack
>> entry (that we're going to free) any more.
>>
>> And add the warning to see if this actually ever triggers (and because
>> I'd like to see the callchain when it does, to see if it's another
>> waitqueue somewhere or what..)
>
> ------------[ cut here ]------------
> WARNING: CPU: 22 PID: 14012 at mm/shmem.c:2668 shmem_fallocate+0x9a7/0xac0
> Kernel panic - not syncing: panic_on_warn set ...

So I noticed that panic_on_warn just after sending the email and I've
been waiting for it it to trigger again.

The warning has triggered twice more without panic_on_warn set and I
haven't seen any crash yet.


Vegard