Subject: CVE-2021-47253: drm/amd/display: Fix potential memory leak in DMUB hw_init

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

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

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

drm/amd/display: Fix potential memory leak in DMUB hw_init

[Why]
On resume we perform DMUB hw_init which allocates memory:
dm_resume->dm_dmub_hw_init->dc_dmub_srv_create->kzalloc
That results in memory leak in suspend/resume scenarios.

[How]
Allocate memory for the DC wrapper to DMUB only if it was not
allocated before.
No need to reallocate it on suspend/resume.

The Linux kernel CVE team has assigned CVE-2021-47253 to this issue.

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

	Fixed in 5.10.45 with commit 9e8c2af01046
	Fixed in 5.12.12 with commit aa000f828e60
	Fixed in 5.13 with commit c5699e2d863f

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-2021-47253
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/display/amdgpu_dm/amdgpu_dm.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/9e8c2af010463197315fa54a6c17e74988b5259c
	https://git.kernel.org/stable/c/aa000f828e60ac15d6340f606ec4a673966f5b0b
	https://git.kernel.org/stable/c/c5699e2d863f58221044efdc3fa712dd32d55cde