apport information
** Tags added: apport-collected zena
** Description changed:
## Summary
Kernel 6.8.0-147 (noble, installed 2026-10-13) introduced a severe regression
in
how often a latent HP firmware ACPI Embedded-Controller mutex bug is
triggered on
an HP EliteBook 860 G10. On 6.8.0-146 the deadlock occurs roughly once every
few
days; on 6.8.0-147 it occurs multiple times per day, sometimes within ~10
minutes
of boot, hard-locking systemd (PID 1) and requiring SysRq REISUB. Reverting to
6.8.0-146 restores normal (rare deadlock) behaviour.
## Hardware
- HP EliteBook 860 16 inch G10 Notebook PC
- BIOS: HP V70 Ver. 01.12.00, 2026-02-04 (latest available)
- CPU: Intel (Raptor Lake), i915 integrated graphics
## Root cause vs regression
- Root cause is an HP firmware/AML bug: a thread acquires the ACPI `[ECMX]`
Embedded-Controller mutex via `\_SB.AC._PSR` (AC-adapter power-source read)
and
never releases it. This is HP's to fix and is not kernel-introduced.
- The REGRESSION is that 6.8.0-147 triggers this firmware race far more often
than
6.8.0-146, turning a rare annoyance into an unusable machine.
## Log signature (at moment of each deadlock)
kernel: ACPI Error: Thread <A> cannot release Mutex [ECMX] acquired by
thread <B> (20230628/exmutex-378)
kernel: ACPI: \_SB_.AC__: Error reading AC Adapter state: AE_AML_NOT_OWNER
Followed by hung EC event processing, then thermald/upowerd/kworker hangs,
then
systemd PID 1 hang and total D-Bus service-activation failure.
## Regression range
- Good: 6.8.0-146 (and earlier: -139, -138, -137). Rare deadlocks (days
apart).
- Bad: 6.8.0-147. Frequent deadlocks (multiple per day).
- -147 is stable patchset LP: #2168026.
## Suspected commits (not bisected)
1. PRIME: "ACPI: AC: Properly notify power management core about changes"
— hits the exact AC._PSR path that grabs [ECMX]; plausibly increases _PSR
evaluation frequency.
2. cpuidle menu governor cluster ("Remove iowait influence", "Select polling
state in some more cases", plus a mid-series revert) — alters CPU idle/wake
timing and hence EC poll frequency.
3. ACPICA lock/opregion changes (evxfregn ContextMutex, "Allow to skip Global
Lock initialization", acpi_ev_address_space_dispatch NULL-deref,
acpi_execute_reg_methods depth arg) — touch EC opregion/mutex machinery.
## Requested outcome
Given the root cause is HP firmware, a DMI-based quirk for this model
(EliteBook
860 G10) that restores -146 AC-notify / idle behaviour, or a revert of the
offending change on affected hardware, would fix this for all affected users.
## Reproduction
Boot 6.8.0-147 on an affected machine and use normally; deadlock typically
occurs within minutes to a couple of hours. Does not occur (or very rarely)
on 6.8.0-146.
## Workaround in place
Pinned GRUB default to 6.8.0-146.
## Attachments (single archive: ecmx-bug-report.tar.gz)
Required by the kernel bug template:
- version.log (/proc/version_signature — note: shows -146, the GOOD
kernel, as that is what is currently booted; -147
is the
bad one, see "Regression range" above)
- lspci-vnvn.log (sudo lspci -vnvn, full)
Supporting evidence:
- system-info.txt (model, BIOS, installed kernels, running kernel)
- cmdline.txt (/proc/cmdline)
- cpuinfo.txt (/proc/cpuinfo)
- dmesg-boot-minus5-full.txt (full kernel log from a deadlock boot)
- ecmx-logs-boot-minus5.txt (ECMX + AC._PSR + AE_AML_NOT_OWNER signatures)
- ecmx-logs-boot-minus8.txt (same, a second deadlock boot)
- acpi-tables/ (DSDT, SSDT1-29, FACP — raw ACPI tables containing
the
_PSR/[ECMX] AML; verified free of serial number /
UUID)
+ ---
+ ProblemType: Bug
+ ApportVersion: 2.28.3-0ubuntu0.1
+ Architecture: amd64
+ AudioDevicesInUse:
+ USER PID ACCESS COMMAND
+ /dev/snd/controlC0: richard 2715 F.... pipewire
+ richard 2718 F.... wireplumber
+ /dev/snd/seq: richard 2715 F.... pipewire
+ CasperMD5CheckMismatches: ./boot/grub/efi.img
+ CasperMD5CheckResult: fail
+ CurrentDesktop: X-Cinnamon
+ DistroRelease: Linux Mint 22.3
+ InstallationDate: Installed on 2024-05-16 (893 days ago)
+ InstallationMedia: Linux Mint 21.3 "Virginia" - Release amd64 20240109
+ MachineType: HP HP EliteBook 860 16 inch G10 Notebook PC
+ NonfreeKernelModules: zfs
+ Package: linux (not installed)
+ ProcEnviron:
+ LANG=en_GB.UTF-8
+ LANGUAGE=en_GB:en
+ PATH=(custom, no user)
+ SHELL=/bin/bash
+ TERM=xterm-256color
+ ProcFB: 0 i915drmfb
+ ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-6.8.0-147-generic
root=/dev/mapper/vgmint-root ro quiet splash acpi_backlight=native atkbd.reset=1
+ ProcVersionSignature: Ubuntu 6.8.0-147.147-generic 6.8.12
+ PulseList: Error: command ['pacmd', 'list'] failed with exit code 1: No
PulseAudio daemon running, or not running as session daemon.
+ RelatedPackageVersions:
+ linux-restricted-modules-6.8.0-147-generic N/A
+ linux-backports-modules-6.8.0-147-generic N/A
+ linux-firmware 20240318.git3b128b60.0ubuntu3.1
+ Tags: zena
+ Uname: Linux 6.8.0-147-generic x86_64
+ UpgradeStatus: No upgrade log present (probably fresh install)
+ UserGroups: N/A
+ _MarkForUpload: True
+ dmi.bios.date: 02/04/2026
+ dmi.bios.release: 12.0
+ dmi.bios.vendor: HP
+ dmi.bios.version: V70 Ver. 01.12.00
+ dmi.board.name: 8B41
+ dmi.board.vendor: HP
+ dmi.board.version: KBC Version 51.46.00
+ dmi.chassis.type: 10
+ dmi.chassis.vendor: HP
+ dmi.ec.firmware.release: 81.70
+ dmi.modalias:
dmi:bvnHP:bvrV70Ver.01.12.00:bd02/04/2026:br12.0:efr81.70:svnHP:pnHPEliteBook86016inchG10NotebookPC:pvrSBKPFV3:rvnHP:rn8B41:rvrKBCVersion51.46.00:cvnHP:ct10:cvr:sku8A483EA#ABU:
+ dmi.product.family: 103C_5336AN HP EliteBook
+ dmi.product.name: HP EliteBook 860 16 inch G10 Notebook PC
+ dmi.product.sku: 8A483EA#ABU
+ dmi.product.version: SBKPFV3
+ dmi.sys.vendor: HP
** Attachment added: "AlsaInfo.txt"
https://bugs.launchpad.net/bugs/2171947/+attachment/6012736/+files/AlsaInfo.txt
--
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/2171947
Title:
6.8.0-147 regression: massively increased frequency of ACPI [ECMX] EC-
mutex deadlock on HP EliteBook 860 G10 (AC._PSR), -146 unaffected
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2171947/+subscriptions
--
ubuntu-bugs mailing list
[email protected]
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
