[TTM] Buffer eviction failed

[PayTech]

I am also running into this problem on a proxmox machine running 7.4-17 with a VM running Linux Mint 22 Cinnamon 6.2.9 with kernel version 6.8.0-47-generic. This proxmox machine previously has had no issues running VMs for weeks at a time. So I'm prone to thinking its something wrong with the VM as when I start VMs with older OS's it will still run for long periods of time (weeks/months) without error. This issue has persisted through to a second proxmox machine running 8.2.7 where the first Linux Mint VM was copied over to the machine. As a test I installed a VM with PopOS 22.04 LTS with kernel version 6.9.3-76060903-generic and the QXL error has occured there too.

I'm going to transfer one of the VMs that I have not had a problem with over to the 8.2.7 proxmox machine and see if i get a QXL error.

If anyone has some recommended tests they would like me to do to help solve this problem I would be more than happy to assist!

 

[THX1138]

No joy on any permutation or combination of RAM/VRAM and vgamem settings - for me, the QXL error occurs in all cases and still seems to be random.

Edit:
Assuming I'm reading it right, after reading through the kernel changelog for Ubuntu's 6.8.0-48 kernel (covering e.g. Ubuntu 24.04, Linux Mint 22 and others if the most up-to-date kernel is installed), it seems that the following occured with regard to the alleged QXL driver bug fix, the discussion of which I previously linked to:

14 Jun 2024
Reverted "drm/qxl: simplify qxl_fence_wait" in upstream kernel 6.8.7, which was pulled into Ubuntu 6.8.0-1008.8-22.04.1 [6.8.0-38.38]

19 Jul 2024
Reapplied "drm/qxl: simplify qxl_fence_wait" in upstream kernel 6.8.10, which was pulled into Ubuntu 6.8.0-1010.10-22.04.1 [6.8.0-40.40]

What's not clear is whether the bug had actually been fixed when the code was reapplied (in 6.8.0-40) or whether it was reapplied in original (buggy) form awaiting a future fix.

To answer my own question, from kernel.org's changelog for upstream kernel 6.8.10:

commit 3dfe35d8683daf9ba69278643efbabe40000bbf6
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon May 6 13:28:59 2024 -0700

Reapply "drm/qxl: simplify qxl_fence_wait"

commit 3628e0383dd349f02f882e612ab6184e4bb3dc10 upstream.

This reverts commit 07ed11afb68d94eadd4ffc082b97c2331307c5ea.

Stephen Rostedt reports:
"I went to run my tests on my VMs and the tests hung on boot up.
Unfortunately, the most I ever got out was:

[ 93.607888] Testing event system initcall: OK
[ 93.667730] Running tests on all trace events:
[ 93.669757] Testing all events: OK
[ 95.631064] ------------[ cut here ]------------
Timed out after 60 seconds"

and further debugging points to a possible circular locking dependency
between the console_owner locking and the worker pool locking.

Reverting the commit allows Steve's VM to boot to completion again.

[ This may obviously result in the "[TTM] Buffer eviction failed"
messages again, which was the reason for that original revert. But at
this point this seems preferable to a non-booting system... ]

Reported-and-bisected-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20240502081641.457aa25f@gandalf.local.home/

So, any downstream (distro) kernel that pulls from upstream linux kernel <6.8.7 or >=6.8.10 will have the buggy QXL code. That's for the 6.8 series; other kernel series probably also have the buggy code (e.g. 5.15).

For Ubuntu and derivatives, it looks like kernels 6.8.0-38 and 6.8.0-39 have the reverted code, so I'll see if I can test those.

 

[jebbam]

I have seen this in Debian bullseye, bookworm, trixie, and sid. It has been around for a lot of different kernel versions.

 

[THX1138]

I have seen this in Debian bullseye, bookworm, trixie, and sid. It has been around for a lot of different kernel versions.

Yes, originally some 3-4 years ago when the QXL driver was first simplified. It's probably in most kernel series since then. But I'm only testing the 6.8 series at the moment.