linux-kernel - Re: [syzbot] WARNING in call_timer

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-next>] [day] [month] [year] [list]

Message-ID: <87wn7tlg4n.ffs@tglx>
Date:   Thu, 17 Nov 2022 17:06:48 +0100
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Hillf Danton <hdanton@...a.com>
Cc:     syzbot <syzbot+6fb78d577e89e69602f9@...kaller.appspotmail.com>,
        linux-kernel@...r.kernel.org, pbonzini@...hat.com,
        syzkaller-bugs@...glegroups.com,
        Steven Rostedt <rosted@...dmis.org>,
        Marcel Holtmann <marcel@...tmann.org>,
        Luiz Augusto von Dentz <luiz.dentz@...il.com>
Subject: Re: [syzbot] WARNING in call_timer_fn

On Thu, Nov 17 2022 at 20:55, Hillf Danton wrote:
> On 17 Nov 2022 12:54:28 +0100 Thomas Gleixner <tglx@...utronix.de>
>> 
>> The work has been canceled already before in the same function and there
>> are some more delayed works which can trigger this.
>> 
>> So no, this whole close_sync() function is prone to teardown races and
>> just slapping a single cancel here without deeper analysis does not cut
>> it.
>
> Agree.
>
> A set of sync cancelations can do the job, given what is defined in struct
> hci_dev wrt workqueue.

It's only part of the solution because you also have to prevent that
work is queued from other parts of the code....