CVE-2026-46292: pmdomain: core: Fix detach procedure for virtual devices in genpd

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

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

pmdomain: core: Fix detach procedure for virtual devices in genpd

If a device is attached to a PM domain through genpd_dev_pm_attach_by_id(),
genpd calls pm_runtime_enable() for the corresponding virtual device that
it registers. While this avoids boilerplate code in drivers, there is no
corresponding call to pm_runtime_disable() in genpd_dev_pm_detach().

This means these virtual devices are typically detached from its genpd,
while runtime PM remains enabled for them, which is not how things are
designed to work. In worst cases it may lead to critical errors, like a
NULL pointer dereference bug in genpd_runtime_suspend(), which was recently
reported. For another case, we may end up keeping an unnecessary vote for a
performance state for the device.

To fix these problems, let's add this missing call to pm_runtime_disable()
in genpd_dev_pm_detach().

The Linux kernel CVE team has assigned CVE-2026-46292 to this issue.


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

	Issue introduced in 4.18 with commit 3c095f32a92be4d07f3172a777dab1aacdb6a728 and fixed in 6.6.141 with commit 707cb5df3eab32ddc52979418f7ace62941e6381
	Issue introduced in 4.18 with commit 3c095f32a92be4d07f3172a777dab1aacdb6a728 and fixed in 6.12.88 with commit 361518a26e4434e879db6ff43bf364795dcbfbff
	Issue introduced in 4.18 with commit 3c095f32a92be4d07f3172a777dab1aacdb6a728 and fixed in 6.18.30 with commit 51a7dd9cbae9210335ce398642ecaaa52c939eb5
	Issue introduced in 4.18 with commit 3c095f32a92be4d07f3172a777dab1aacdb6a728 and fixed in 7.0.7 with commit 8d44391a7f29e4601e8243f13498d0219bab2576
	Issue introduced in 4.18 with commit 3c095f32a92be4d07f3172a777dab1aacdb6a728 and fixed in 7.1-rc3 with commit 26735dfdd8930d9ef1fa92e590a9bf77726efdf6

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-2026-46292
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/pmdomain/core.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/707cb5df3eab32ddc52979418f7ace62941e6381
	https://git.kernel.org/stable/c/361518a26e4434e879db6ff43bf364795dcbfbff
	https://git.kernel.org/stable/c/51a7dd9cbae9210335ce398642ecaaa52c939eb5
	https://git.kernel.org/stable/c/8d44391a7f29e4601e8243f13498d0219bab2576
	https://git.kernel.org/stable/c/26735dfdd8930d9ef1fa92e590a9bf77726efdf6