Public bug reported:
Kernel: 7.0.0-38-generic #38-Ubuntu (Ubuntu 26.04.1 LTS,
linux-image-generic-hwe-26.04)
Hardware: Acer Nitro ANV15-51 (i5-13420H, Intel UHD + NVIDIA RTX 4050,
nvidia-driver-595-open), BIOS V1.60
snapd: experimental.apparmor-prompting=true (enabled at the time of the freezes)
Symptom:
The system hard-freezes several times a day. No panic, no kdump (kdump is
loaded,
and softlockup/hardlockup/hung_task panic were enabled), nothing in the journal
at
the moment of the freeze. Minutes to hours before each freeze, the kernel logs
this
warning, increasingly often and sometimes on two CPUs at once:
WARNING: kernel/workqueue.c:2351 at __queue_work.part.0+0x190/0x390, CPU#11:
swapper/11/0
Tainted: [W]=WARN, [O]=OOT_MODULE
Call Trace:
<IRQ>
__queue_work+0x39/0xc0
delayed_work_timer_fn+0x19/0x30
call_timer_fn+0x30/0x170
__run_timers+0x1af/0x2c0
run_timer_softirq+0x8a/0x100
handle_softirqs+0xe1/0x360
...
sysvec_apic_timer_interrupt+0x9f/0xd0
</IRQ>
(also seen in process context: "CPU#6: gnome-shell" and "CPU#8: firefox"
at the same instant)
The work item has work->entry not empty while not marked pending, i.e. a delayed
work that was re-initialized or freed while still queued.
Identifying the owner:
I attached a bpftrace kprobe to delayed_work_timer_fn that prints the work
function
when work->entry is not empty:
$dw = (struct delayed_work *)(arg0 - 32);
if ((uint64)$dw->work.entry.next != (uint64)$dw + 8)
printf("SUSPEITO: %s\n", ksym($dw->work.func));
Every time the WARN fires, the probe reports:
audit_cache_work_function
It is built-in (no module in /proc/kallsyms). Its neighbours in kallsyms are
__aa_ip_localout and notification_match, i.e. the AppArmor
notification/prompting
SAUCE code. Possibly related to CVE-2026-47330 (uninitialized variable in
AppArmor
SAUCE notification handling), but I can't confirm.
Timeline: 7.0.0-38 installed 2026-10-08; WARNs first appeared 2026-10-16;
since then 2-7 WARNs per boot, each boot ending in a freeze.
auditd is not running, no third-party LSM/security modules loaded.
Workaround being tested: snap set system experimental.apparmor-prompting=false
(will update this report with the result).
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: linux-image-7.0.0-38-generic 7.0.0-38.38
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun Oct 18 03:32:30 2026
InstallationDate: Installed on 2026-10-08 (9 days ago)
InstallationMedia: Ubuntu 26.04.1 LTS "Resolute Raccoon" - Release amd64
(20260826)
MachineType: Acer Nitro ANV15-51
ProcEnviron:
LANG=pt_BR.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
ProcFB:
0 i915drmfb
1 nvidia-drmdrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-7.0.0-38-generic
root=/dev/mapper/ubuntu--vg-ubuntu--lv ro quiet splash
nvme_core.default_ps_max_latency_us=0 pcie_aspm=off
crashkernel=2G-4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/08/2026
dmi.bios.release: 1.60
dmi.bios.vendor: INSYDE Corp.
dmi.bios.version: V1.60
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: Sportage_RTH
dmi.board.vendor: RPL
dmi.board.version: V1.60
dmi.chassis.type: 10
dmi.chassis.vendor: Acer
dmi.chassis.version: Chassis Version
dmi.ec.firmware.release: 1.8
dmi.modalias:
dmi:bvnINSYDECorp.:bvrV1.60:bd04/08/2026:br1.60:efr1.8:svnAcer:pnNitroANV15-51:pvrV1.60:rvnRPL:rnSportage_RTH:rvrV1.60:cvnAcer:ct10:cvrChassisVersion:sku0000000000000000:pfaAcerNitroV15:
dmi.product.family: Acer Nitro V 15
dmi.product.name: Nitro ANV15-51
dmi.product.sku: 0000000000000000
dmi.product.version: V1.60
dmi.sys.vendor: Acer
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute wayland-session
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https://bugs.launchpad.net/bugs/2171316
Title:
AppArmor SAUCE: corrupted delayed work in audit_cache_work_function
(workqueue.c:2351 WARN) followed by hard system freeze, with apparmor-
prompting enabled
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