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From:   Daniel Stone <daniel@fooishbar.org>
Date:   Tue, 19 Sep 2023 07:38:52 +0100
Message-ID: <CAPj87rNAv_ACFJF_PbWnJjjmSrSOvfVuvOHq9mmza5w=t+BF0w@mail.gmail.com>
Subject: Re: drm/vkms: deadlock between dev->event_lock and timer
To:     Helen Koike <helen.koike@collabora.com>
Cc:     Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
        Maira Canal <mairacanal@riseup.net>,
        Arthur Grillo <arthurgrillo@riseup.net>,
        Rodrigo Siqueira <rodrigosiqueiramelo@gmail.com>,
        Melissa Wen <melissa.srw@gmail.com>,
        Haneen Mohammed <hamohammed.sa@gmail.com>,
        David Airlie <airlied@gmail.com>,
        DRI <dri-devel@lists.freedesktop.org>,
        syzkaller@googlegroups.com, LKML <linux-kernel@vger.kernel.org>,
        Hillf Danton <hdanton@sina.com>,
        Sanan Hasanov <Sanan.Hasanov@ucf.edu>,
        Thomas Gleixner <tglx@linutronix.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Daniel Stone <daniels@collabora.com>,
        David Heidelberg <david.heidelberg@collabora.com>,
        Vignesh Raman <vignesh.raman@collabora.com>
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On Mon, 18 Sept 2023 at 23:02, Helen Koike <helen.koike@collabora.com> wrote:
> On 14/09/2023 05:12, Daniel Vetter wrote:
> > Also yes how that landed without anyone running lockdep is ... not good. I
> > guess we need a lockdep enabled drm ci target that runs vkms tests asap
> > :-)
>
> btw, I just executed a draft version of vkms targed on the ci, we do get
> the warning:
>
> https://gitlab.freedesktop.org/helen.fornazier/linux/-/jobs/49156305#L623
>
> I'm just not sure if tests would fail (since it is a warning) and it has
> a chance to be ignored if people don't look at the logs (unless if igt
> already handles that).

Hmm, dmesg-warn is already a separate igt test status. I guess it just
needs to be handled explicitly.

> I still need to do some adjustments (it seems the tests is hanging
> somewhere and we got a timeout) but we should have vkms in drm ci soon.

Might be due to the locking explosion? The kernels should probably
have soft-lockup detection enabled as well as lockdep.

Cheers,
Daniel