Subject: CVE-2021-47362: drm/amd/pm: Update intermediate power state for SI

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

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

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

drm/amd/pm: Update intermediate power state for SI

Update the current state as boot state during dpm initialization.
During the subsequent initialization, set_power_state gets called to
transition to the final power state. set_power_state refers to values
from the current state and without current state populated, it could
result in NULL pointer dereference.

For ex: on platforms where PCI speed change is supported through ACPI
ATCS method, the link speed of current state needs to be queried before
deciding on changing to final power state's link speed. The logic to query
ATCS-support was broken on certain platforms. The issue became visible
when broken ATCS-support logic got fixed with commit
f9b7f3703ff9 ("drm/amdgpu/acpi: make ATPX/ATCS structures global (v2)").

Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1698

The Linux kernel CVE team has assigned CVE-2021-47362 to this issue.

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

	Fixed in 5.10.70 with commit 68d4fbe6220c
	Fixed in 5.14.9 with commit 06a18e64256f
	Fixed in 5.15 with commit ab39d3cef526

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-2021-47362
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/powerplay/si_dpm.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/68d4fbe6220cd1f3d07cab0a4901e62f8c12cc68
	https://git.kernel.org/stable/c/06a18e64256f7aecb5a27df02faa3568fcd3c105
	https://git.kernel.org/stable/c/ab39d3cef526ba09c4c6923b4cd7e6ec1c5d4faa