CVE-2026-74450: drm/amd/pm: fix pptable use-after-free

From: Greg Kroah-Hartman <[email protected]>

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

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

drm/amd/pm: fix pptable use-after-free

amdgpu_dpm_get_pp_table() returns a pointer to a driver-owned power table
after dropping adev->pm.mutex. The sysfs path then copies from that pointer.
A concurrent pp_table write can replace and free the allocation during the
copy, causing a use-after-free.

Change the DPM interface to copy into caller-provided storage while the mutex
is held. Keep the size-only query for attribute discovery without exposing
the driver-owned pointer.

(cherry picked from commit f6eed7acfd30099ef7baeb6ba45bb59daad80631)

The Linux kernel CVE team has assigned CVE-2026-74450 to this issue.


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

	Issue introduced in 4.9 with commit 1684d3ba488529266ce6f97b88076bd185f4790e and fixed in 7.1.8 with commit b628f2c6feb3a115ea72d3120a2bd94afc5163df
	Issue introduced in 4.9 with commit 1684d3ba488529266ce6f97b88076bd185f4790e and fixed in 7.2-rc6 with commit bb493058c35c8676e48269ab6732688ea733d23c

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-2026-74450
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/gpu/drm/amd/pm/amdgpu_dpm.c
	drivers/gpu/drm/amd/pm/amdgpu_pm.c
	drivers/gpu/drm/amd/pm/inc/amdgpu_dpm.h


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/b628f2c6feb3a115ea72d3120a2bd94afc5163df
	https://git.kernel.org/stable/c/bb493058c35c8676e48269ab6732688ea733d23c