linux-kernel - Re: [BUG][v6.9-rc6] Deadlock with: Revert "drm/qxl: simplify qxl_fence

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] [day] [month] [year] [list]

Date: Wed, 8 May 2024 14:42:38 +0200
From: Anders Blomdell <anders.blomdell@...il.com>
To: Steven Rostedt <rostedt@...dmis.org>, David Airlie <airlied@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
 Maxime Ripard <mripard@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
 Alex Constantino <dreaming.about.electric.sheep@...il.com>,
 Timo Lindfors <timo.lindfors@....fi>, Gerd Hoffmann <kraxel@...hat.com>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Thomas Zimmermann <tzimmermann@...e.de>, Daniel Vetter <daniel@...ll.ch>
Subject: Re: [BUG][v6.9-rc6] Deadlock with: Revert "drm/qxl: simplify
 qxl_fence_wait"



On 2024-05-07 11:03, Steven Rostedt wrote:
> On Tue, 7 May 2024 15:54:21 +1000
> David Airlie <airlied@...hat.com> wrote:
> 
>> I expec this will reintroduce the other problems that caused this
>> change in the first place, but I think this should at least bring us
>> back to regression equilibrium. I can't recommend anyone use qxl hw
>> over virtio-gpu hw in their VMs, since virtio-gpu is actually hw
>> designed for virt.
> 
> I agree that it will likely cause the issues that this was addressing
> to come back, but you can't have a fix that introduces a deadlock.
> 
> Perhaps the deadlock didn't exist before, and the printk updates
> changed the way it works to introduce it now?
It deadlocks on 6.8.8 under qemu/kvm,  reverting the patch fixes the problem there as well (6.8.7 hangs as well, but I have not tested reverting on that version)

/Anders