Subject: CVE-2024-49921: drm/amd/display: Check null pointers before used

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

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

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

drm/amd/display: Check null pointers before used

[WHAT & HOW]
Poniters, such as dc->clk_mgr, are null checked previously in the same
function, so Coverity warns "implies that "dc->clk_mgr" might be null".
As a result, these pointers need to be checked when used again.

This fixes 10 FORWARD_NULL issues reported by Coverity.

The Linux kernel CVE team has assigned CVE-2024-49921 to this issue.

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

	Fixed in 6.11.3 with commit 5b35bf1a82eb
	Fixed in 6.12-rc1 with commit be1fb44389ca

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-2024-49921
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/clk_mgr/dce110/dce110_clk_mgr.c
	drivers/gpu/drm/amd/display/dc/hubp/dcn10/dcn10_hubp.c
	drivers/gpu/drm/amd/display/dc/hubp/dcn20/dcn20_hubp.c
	drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
	drivers/gpu/drm/amd/display/dc/hwss/dcn10/dcn10_hwseq.c
	drivers/gpu/drm/amd/display/dc/hwss/dcn31/dcn31_hwseq.c
	drivers/gpu/drm/amd/display/dc/hwss/dcn35/dcn35_hwseq.c
	drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.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/5b35bf1a82eb29841b67ff5643ba83762250fc24
	https://git.kernel.org/stable/c/be1fb44389ca3038ad2430dac4234669bc177ee3