Hi
Am 12.06.24 um 14:41 schrieb Linux regression tracking (Thorsten Leemhuis):
[CCing a few more people and lists that get_maintainers pointed out for qxl]
Hi, Thorsten here, the Linux kernel's regression tracker. Top-posting
for once, to make this easily accessible to everyone.
Thomas, from here it looks like this report that apparently is caused by
a change of yours that went into 6.10-rc1 (b33651a5c98dbd ("drm/qxl: Do
not pin buffer objects for vmap")) fell through the cracks. Or was
progress made to resolve this and I just missed this?
Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
Everything you wanna know about Linux kernel regression tracking:
https://linux-regtracking.leemhuis.info/about/#tldr
If I did something stupid, please tell me, as explained on that page.
#regzbot poke
On 03.06.24 04:29, Kaplan, David wrote:
-----Original Message-----
From: Kaplan, David
Sent: Sunday, June 2, 2024 9:25 PM
To: tzimmermann@xxxxxxx; dmitry.osipenko@xxxxxxxxxxxxx; Koenig,
Christian <Christian.Koenig@xxxxxxx>; zach.rusin@xxxxxxxxxxxx
Cc: Petkov, Borislav <Borislav.Petkov@xxxxxxx>; regressions@xxxxxxxxxxxxxx
Subject: [REGRESSION] QXL display malfunction
Hi,
I am running an Ubuntu 19.10 VM with a tip kernel using QXL video and I've
observed the VM graphics often malfunction after boot, sometimes failing to
load the Ubuntu desktop or even immediately shutting the guest down.
When it does load, the guest dmesg log often contains errors like
[ 4.303586] [drm:drm_atomic_helper_commit_planes] *ERROR* head 1
wrong: 65376256x16777216+0+0
[ 4.586883] [drm:drm_atomic_helper_commit_planes] *ERROR* head 1
wrong: 65376256x16777216+0+0
[ 4.904036] [drm:drm_atomic_helper_commit_planes] *ERROR* head 1
wrong: 65335296x16777216+0+0
I don't see how these messages are related. Did they already appear
before the broken commit was there?
[ 5.374347] [drm:qxl_release_from_id_locked] *ERROR* failed to find id in
release_idr
Is there only one such message in the log? Or multiple/frequent ones.
Could you provide a stack trace of what happens before?
We sometimes draw into the buffer object from the CPU. For accessing the
buffer object's pages from the CPU, only a vmap operation should be
necessary. It appears as if qxl also requires a pin. My guess is that
the pin inserts the buffer-object's host-side pages and the code around
qxl_release_from_id_locked() appears to be garbage-collecting them.
Hence without the pin, the GC complains about inconsistent state.
I bisected the issue down to "drm/qxl: Do not pin buffer objects for vmap"
(b33651a5c98dbd5a919219d8c129d0674ef74299).
Thanks for bisecting. Does it work if you revert that commit?
Best regards
Thomas
The full guest .config and guest XML can be provided if desired. The guest
kernel has QXL support compiled in and the VM has
<video>
<model type="qxl" ram="65536" vram="65536" vgamem="16384"
heads="1" primary="yes"/>
<address type="pci" domain="0x0000" bus="0x00" slot="0x01"
function="0x0"/> </video>
The host is Ubuntu 24.04 (stock) running QEMU version 8.2.2. The VM is run
under virt-manager 4.1.0. If other information would be helpful, just let me
know.
Thanks --David Kaplan
Fixing emails...sorry
--David Kaplan
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)
