Public bug reported:
Environment
- Two cloud VMs (IONOS, QEMU/KVM, i440FX), display device: Red Hat QXL
paravirtual graphic card (rev 05), headless servers running Plesk
- In-place upgrade 24.04 -> 26.04 on Oct 1 2026
Symptom
qxl initializes normally at boot. After a variable time (about 1h to 7.5h), the
kernel logs "[TTM] Buffer eviction failed" every ~15 s and never recovers.
Afterwards systemd-logind fails ("Failed to start user service
'[email protected]': Connection timed out"), PAM CreateSession times out, new SSH
sessions drop, and `reboot` over SSH never completes. Only a hard reset from
the hypervisor works. No OOM, hung-task or I/O messages precede the first
error. Later in the failing boot the kernel logs hung-task reports roughly
every 2 minutes.
The fbdev damage worker (drm_fb_helper_damage_work) is blocked in qxl_fence_wait
(qxl_bo_create -> qxl_alloc_bo_reserved -> qxl_draw_dirty_fb), apparently
waiting on a
fence that is never signaled. Full trace attached.
Evidence (journalctl -k, error counts per boot)
- 6.8.0-136 ... -146 (24.04), 9 boots, Jul-Oct: 0 errors (server A)
- 7.0.0-34: errors on both servers (A: 1,611; B: first error ~7h30m after boot)
- 7.0.0-38: errors on both (A: first at 1h18m, 149,765 errors over ~27 days; B:
first at ~6h18m)
- 7.0.0-42: B failed 1h42m after boot; A ran 5h40m without errors (qxl loaded),
so not a fix
Blacklisting qxl (modprobe.d + initramfs) removes the problem: no errors and
SSH reboot works.
Not known: root cause, or whether it is guest-kernel or QEMU/SPICE-side.
Remote console also ignores keyboard input on these VMs.
Attached: kernel log excerpts (qxl/drm/ttm lines) from the failing
boots, lspci -nnk output.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-42-generic 7.0.0-42.42
ProcVersionSignature: Ubuntu 7.0.0-42.42-generic 7.0.14
Uname: Linux 7.0.0-42-generic x86_64
AlsaDevices:
total 0
crw-rw---- 1 root audio 116, 1 Oct 28 14:19 seq
crw-rw---- 1 root audio 116, 33 Oct 28 14:19 timer
AplayDevices: Error: [Errno 2] No such file or directory: 'aplay'
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
ArecordDevices: Error: [Errno 2] No such file or directory: 'arecord'
AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq',
'/dev/snd/timer'] failed with exit code 1:
CRDA: N/A
CasperMD5CheckResult: unknown
CloudArchitecture: x86_64
CloudBuildName: server
CloudID: nocloud
CloudName: unknown
CloudPlatform: nocloud
CloudSerial: 20240423
CloudSubPlatform: seed-dir (/var/lib/cloud/seed/nocloud)
Date: Wed Oct 28 14:33:59 2026
Lsusb:
Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd QEMU Tablet
Lsusb-t:
/: Bus 001.Port 001: Dev 001, Class=root_hub, Driver=uhci_hcd/2p, 12M
|__ Port 001: Dev 002, If 0, Class=Human Interface Device, Driver=usbhid,
12M
MachineType: QEMU Standard PC (i440FX + PIIX, 1996)
PciMultimedia:
ProcEnviron:
LANG=C.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB:
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-42-generic
root=UUID=8bd862e8-c4b6-4741-b54e-45b3ef5af4c7 ro console=tty1 console=ttyS0
RfKill: Error: [Errno 2] No such file or directory: 'rfkill'
SourcePackage: linux
UpgradeStatus: Upgraded to resolute on 2026-10-01 (27 days ago)
dmi.bios.date: 04/01/2014
dmi.bios.release: 0.0
dmi.bios.vendor: SeaBIOS
dmi.bios.version: 1.16.2-debian-1.16.2-1
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-i440fx-6.1
dmi.modalias:
dmi:bvnSeaBIOS:bvr1.16.2-debian-1.16.2-1:bd04/01/2014:br0.0:svnQEMU:pnStandardPC(i440FX+PIIX,1996):pvrpc-i440fx-6.1:cvnQEMU:ct1:cvrpc-i440fx-6.1:sku:pfa:
dmi.product.name: Standard PC (i440FX + PIIX, 1996)
dmi.product.version: pc-i440fx-6.1
dmi.sys.vendor: QEMU
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: apport-bug drm kvm qxm regression-release resolute
** Attachment added: "sp-qxl-log.txt"
https://bugs.launchpad.net/bugs/2172407/+attachment/6013180/+files/sp-qxl-log.txt
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2172407
Title:
[qxl] "[TTM] Buffer eviction failed" repeats forever, systemd stalls,
on 7.0.0-34/-38/-42 (26.04) on QEMU/KVM; 6.8 fine
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2172407/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
