CVE-2026-90364: ACPI: processor: Unregister cpufreq notifier on init failure

CVE-2026-90364: ACPI: processor: Unregister cpufreq notifier on init failure

[Greg Kroah-Hartman]

From: Greg Kroah-Hartman <gregkh@kernel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

ACPI: processor: Unregister cpufreq notifier on init failure

acpi_processor_driver_init() registers the cpufreq policy notifier before
registering the ACPI processor driver and setting up CPU hotplug state.

If driver_register() or cpuhp_setup_state() fails, the error path only
unregisters the ACPI processor driver and the idle driver. The cpufreq
notifier remains registered even though initialization failed.

Mirror the module exit path on the init failure path and unregister the
cpufreq notifier when it has been registered.

The Linux kernel CVE team has assigned CVE-2026-90364 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.3 with commit c0e0421a60bf468e88cf569fbd727346b138ed04 and fixed in 6.6.157 with commit ccee0785030978c49505e04954eee3f30a5f01ca
	Issue introduced in 6.3 with commit c0e0421a60bf468e88cf569fbd727346b138ed04 and fixed in 6.12.110 with commit 8f3036c5de8b651880f323e223b1604b6cfbff21
	Issue introduced in 6.3 with commit c0e0421a60bf468e88cf569fbd727346b138ed04 and fixed in 6.18.52 with commit 64976f3b34b07eb866ead4052cefe7e9ff45fd2f
	Issue introduced in 6.3 with commit c0e0421a60bf468e88cf569fbd727346b138ed04 and fixed in 7.2.6 with commit 182cd086b31ea4ccc1d8f2ec5b81e988dfe0b892
	Issue introduced in 6.3 with commit c0e0421a60bf468e88cf569fbd727346b138ed04 and fixed in 7.3-rc1 with commit 06f32dd67e6b23a05bef0d8183c5335af91c0c3b

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2026-90364
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/acpi/processor_driver.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/ccee0785030978c49505e04954eee3f30a5f01ca
	https://git.kernel.org/stable/c/8f3036c5de8b651880f323e223b1604b6cfbff21
	https://git.kernel.org/stable/c/64976f3b34b07eb866ead4052cefe7e9ff45fd2f
	https://git.kernel.org/stable/c/182cd086b31ea4ccc1d8f2ec5b81e988dfe0b892
	https://git.kernel.org/stable/c/06f32dd67e6b23a05bef0d8183c5335af91c0c3b