Public bug reported:
Summary
-------
Loading the hp_bioscfg module causes an immediate, complete system lockup
on an HP Laptop 15-bs1xx (consumer model, Broadwell-U). No kernel output,
no response to Caps Lock, network stops, only a forced power-off recovers.
Because the module is auto-loaded via its WMI alias, every normal boot of
Ubuntu 26.04 hangs at systemd-udev-settle. Blacklisting hp_bioscfg makes
the system boot and work normally.
Hardware / firmware
-------------------
Model: HP Laptop 15-bs1xx (marketed as HP 15-bs700), product 7NC27EA#ACB
Board: 8444 (EC firmware 67.33)
CPU: Intel Core i3-5005U (Broadwell-U), Wildcat Point-LP PCH
BIOS: Insyde F.75, release date 04/26/2024 (HP SoftPaq sp153030)
(previously F.72, installed as UEFI capsule via Windows Update
"HP Inc. - Firmware 15.72.0.0")
Boot mode: UEFI, Secure Boot disabled
Software
--------
Ubuntu 26.04.1 LTS live image (20260826), kernel 7.0.0-30-generic
Symptoms
--------
- Any normal boot (with or without nomodeset, quiet/splash removed)
freezes hard around "Starting systemd-udev-settle.service".
- Keyboard LEDs (Caps Lock) stop responding; no panic, no output,
no reaction to SysRq; requires holding the power button.
- acpi=off boots fine.
How the culprit was isolated
----------------------------
1. Booted with ACPI enabled but udev coldplug disabled:
nomodeset systemd.mask=systemd-udev-trigger.service
systemd.mask=systemd-udev-settle.service modules_load=r8169
-> system boots and stays responsive.
2. Loaded the modules matching present devices one at a time, writing a
synced log line to persistent storage before and after each modprobe.
All of these loaded without problems:
intel_oc_wdt lpc_ich i2c_i801 mei_me tpm_tis intel_pch_thermal
rtc_cmos button acpi_pad acpi_cpufreq processor wireless_hotkey
wmi_bmof i8042 snd_hda_intel rtw88_8723de btusb uvcvideo pcspkr
ac battery fan thermal int3400_thermal
processor_thermal_device_pci_legacy hp_wmi
3. "modprobe hp_bioscfg" -> instant hard lockup (log ends with
"START hp_bioscfg", no completion line, host drops off the network).
4. Confirmation: a completely normal boot (i915 KMS, full udev coldplug,
all drivers) with only
modprobe.blacklist=hp_bioscfg
reaches multi-user.target and runs fine (i915, hp_wmi, rtw88_8723de,
snd_hda_intel, battery all loaded, 4 CPUs online).
WMI GUIDs present on this machine
---------------------------------
05901221-D566-11D1-B2F0-00A0C9062910
14EA9746-CE1F-4098-A0E0-7045CB4DA745
1F4C91EB-DC5C-460B-951D-C7CB9B4B8D5E
2B814318-4BE8-4707-9D84-A190A859B5D0
2D114B49-2DFB-4130-B8FE-4A3C09E75133
322F2028-0F84-4901-988E-015176049E2D
5FB7F034-2C63-45E9-BE91-3D44E2C707E4 <- hp_bioscfg binds here
95F24279-4D7B-4334-9387-ACCDC67EF61C
988D08E3-68F4-4C35-AF3E-6A1B8106F83C
Expected behaviour
------------------
hp_bioscfg should not be able to hard-lock a consumer HP machine. The
firmware's BIOS-configuration WMI method apparently never returns on this
model (likely an SMI that does not come back), so a DMI-based denylist for
consumer models, or a safer probe that does not issue the blocking call,
would avoid the issue.
Workaround
----------
/etc/modprobe.d/hp-bioscfg-off.conf:
blacklist hp_bioscfg
install hp_bioscfg /bin/false
plus "modprobe.blacklist=hp_bioscfg" on the kernel command line for the
installer / live session.
Available on request
--------------------
acpidump of the machine, full dmesg of a good boot (with the blacklist),
lspci -nn, the per-module load log.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: 26.04.01 hp laptop
--
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https://bugs.launchpad.net/bugs/2172653
Title:
hp_bioscfg: hard system lockup on module load on HP Laptop 15-bs1xx
(board 8444, BIOS F.75)
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