Subject: CVE-2024-49907: drm/amd/display: Check null pointers before using dc->clk_mgr

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

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

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

drm/amd/display: Check null pointers before using dc->clk_mgr

[WHY & HOW]
dc->clk_mgr is null checked previously in the same function, indicating
it might be null.

Passing "dc" to "dc->hwss.apply_idle_power_optimizations", which
dereferences null "dc->clk_mgr". (The function pointer resolves to
"dcn35_apply_idle_power_optimizations".)

This fixes 1 FORWARD_NULL issue reported by Coverity.

The Linux kernel CVE team has assigned CVE-2024-49907 to this issue.

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

	Fixed in 5.10.227 with commit 8d54001f8dcc
	Fixed in 5.15.168 with commit a545a9403e04
	Fixed in 6.1.113 with commit a2773e0a4b79
	Fixed in 6.6.55 with commit 9641bc4adf84
	Fixed in 6.10.14 with commit 3f7e533c10db
	Fixed in 6.11.3 with commit 5ba3fbf75b24
	Fixed in 6.12-rc1 with commit 95d9e0803e51

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-2024-49907
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/dc/core/dc.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/8d54001f8dccd56146973f23f3ab2ba037a21251
	https://git.kernel.org/stable/c/a545a9403e04c6e17fdc04a26a61d9feebbba106
	https://git.kernel.org/stable/c/a2773e0a4b79e7a6463abdffaf8cc4f24428ba18
	https://git.kernel.org/stable/c/9641bc4adf8446034e490ed543ae7e9833cfbdf5
	https://git.kernel.org/stable/c/3f7e533c10db3d0158709a99e2129ff63add6bcd
	https://git.kernel.org/stable/c/5ba3fbf75b243b2863a8be9e7c393e003d3b88f3
	https://git.kernel.org/stable/c/95d9e0803e51d5a24276b7643b244c7477daf463