Public bug reported:

A KVM/QEMU guest on Ubuntu 22.04 (Jammy, HWE kernel 6.8.0-79-generic)
hits a kernel oops with “Bad pagetable: 000d” while a Java GUI
(AWT/JavaFX) is active. Kdump triggers and captures a vmcore. First
noticed after updating to 6.8.0-79; comparison with 6.8.0-78 is pending
(I will test -78 next and report back).

Environment
- Guest OS: Ubuntu 22.04.4 (Jammy) with HWE kernel 6.8.0-79-generic
- Virtualization: KVM/QEMU, machine type Q35
- Guest GPU: virtio GPU [1af4:1050] (virgl, 3D accel forced to drive 5120x1440 
monitor)
- Mesa stack in guest: 23.2.1-1ubuntu3.1~22.04.3
  - glxinfo -B shows: vendor Mesa; renderer “virgl (AMD Radeon Graphics 
(radeonsi, raphael_mendocino, …))”
- lspci: “00:01.0 VGA compatible controller: Red Hat, Inc. Virtio GPU 
[1af4:1050]”
- Kernel cmdline (guest):
  workqueue.default_to_unbound=1 console=ttyS0,115200n8 console=tty0 panic=10 
loglevel=7 systemd.show_status=1 drm.debug=0x1e crashkernel=512M-:192M

Symptom / oops signature
- Console shows:
  - “AWT-EventQueue-: Corrupted page table at address 8038358c”
  - “Bad pagetable: 000d [#1] PREEMPT SMP NOPTI”
- Oops path from vmcore (crash(8)):
  pgtable_bad → do_user_addr_fault → exc_page_fault → asm_exc_page_fault → 
crash_kexec
- Example PTE that triggered:
  PTE 0x8000000299d39867 → PHYS 0x299d39000 FLAGS: 
PRESENT|RW|USER|ACCESSED|DIRTY|NX
- Task at oops time:
  PID 11858, COMM "AWT-EventQueue-" (JVM GUI thread)
- Hardware banner in oops:
  “QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2”

Frequency / workload
- Reproduced under interactive GUI load in the VM (Java AWT/JavaFX 
application). Prior lines in dmesg show frequent DRM atomic FB flips from 
virtio_gpu while the desktop/app is active.

What I collected
- kdump vmcore + dmesg from crash (vmcore: 
/var/crash/202509090957/dump.202509090957; dmesg saved)
- guest serial console log and QMP event log from the host during the incident
- full kernel command line and module list, Mesa/GLx info, and lspci output

What I’m about to try
- Boot the same guest with 6.8.0-78-generic (vmlinuz.old/initrd.img.old) to 
determine if this is a 6.8.0-79 regression or not; I will update the bug with 
results.
- If requested, I can also try a -proposed HWE build for confirmation.

Questions for triage
- Does this look like a kernel-side virtio_gpu/DRM/MM issue vs. a userspace 
virglrenderer trigger?
- Any known fixes in later 6.8 HWE updates that match this signature?

Tags (suggested): jammy hwe kernel oops kdump kvm qemu virtio-gpu drm virgl mesa
Attachments available on request:
- vmcore + dmesg from kdump
- guest journal/dmesg around the oops
- serial console log and QMP events from host
- `glxinfo -B`, `lspci -nnk`, `/proc/cmdline`

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: linux-image-6.8.0-79-generic 6.8.0-79.79~22.04.1
ProcVersionSignature: Ubuntu 6.8.0-79.79~22.04.1-generic 6.8.12
Uname: Linux 6.8.0-79-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.10
Architecture: amd64
AudioDevicesInUse:
 USER        PID ACCESS COMMAND
 /dev/snd/controlC0:  joes       1455 F.... pulseaudio
CRDA: N/A
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Tue Sep  9 13:25:08 2025
InstallationDate: Installed on 2025-07-21 (49 days ago)
InstallationMedia: Ubuntu 22.04.5 LTS "Jammy Jellyfish" - Release amd64 
(20240911)
IwConfig:
 lo        no wireless extensions.
 
 enp1s0    no wireless extensions.
Lsusb:
 Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
 Bus 001 Device 002: ID 0627:0001 Adomax Technology Co., Ltd QEMU USB Tablet
 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Lsusb-t:
 /:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 5000M
 /:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M
     |__ Port 1: Dev 2, If 0, Class=Human Interface Device, Driver=usbhid, 480M
MachineType: QEMU Standard PC (Q35 + ICH9, 2009)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 virtio_gpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-6.8.0-79-generic 
root=UUID=e7a3ebd8-b568-463d-96c4-cf8270ba34d3 ro 
workqueue.default_to_unbound=1 console=ttyS0,115200n8 console=tty0 panic=10 
loglevel=7 systemd.show_status=1 drm.debug=0x1e crashkernel=512M-:192M
RelatedPackageVersions:
 linux-restricted-modules-6.8.0-79-generic N/A
 linux-backports-modules-6.8.0-79-generic  N/A
 linux-firmware                            20220329.git681281e4-0ubuntu3.39
RfKill:
 
SourcePackage: linux-hwe-6.8
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/01/2014
dmi.bios.release: 0.0
dmi.bios.vendor: SeaBIOS
dmi.bios.version: 1.16.3-debian-1.16.3-2
dmi.chassis.type: 1
dmi.chassis.vendor: QEMU
dmi.chassis.version: pc-q35-8.2
dmi.modalias: 
dmi:bvnSeaBIOS:bvr1.16.3-debian-1.16.3-2:bd04/01/2014:br0.0:svnQEMU:pnStandardPC(Q35+ICH9,2009):pvrpc-q35-8.2:cvnQEMU:ct1:cvrpc-q35-8.2:sku:
dmi.product.name: Standard PC (Q35 + ICH9, 2009)
dmi.product.version: pc-q35-8.2
dmi.sys.vendor: QEMU

** Affects: linux-hwe-6.8 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug jammy wayland-session

** Attachment added: "crash.tgz"
   https://bugs.launchpad.net/bugs/2122445/+attachment/5908041/+files/crash.tgz

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https://bugs.launchpad.net/bugs/2122445

Title:
  Jammy HWE 6.8.0-79 in KVM/QEMU guest (virtio_gpu/virgl): kernel oops
  “Bad pagetable: 000d” in do_user_addr_fault while running Java
  AWT/JavaFX GUI

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