Subject: CVE-2024-26662: drm/amd/display: Fix 'panel_cntl' could be null in 'dcn21_set_backlight_level()'

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

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

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

drm/amd/display: Fix 'panel_cntl' could be null in 'dcn21_set_backlight_level()'

'panel_cntl' structure used to control the display panel could be null,
dereferencing it could lead to a null pointer access.

Fixes the below:
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn21/dcn21_hwseq.c:269 dcn21_set_backlight_level() error: we previously assumed 'panel_cntl' could be null (see line 250)

The Linux kernel CVE team has assigned CVE-2024-26662 to this issue.

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

	Issue introduced in 5.9 with commit 474ac4a875ca and fixed in 6.6.17 with commit 2e150ccea131
	Issue introduced in 5.9 with commit 474ac4a875ca and fixed in 6.7.5 with commit 0c863cab0e91
	Issue introduced in 5.9 with commit 474ac4a875ca and fixed in 6.8 with commit e96fddb32931

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-2024-26662
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/hwss/dcn21/dcn21_hwseq.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/2e150ccea13129eb048679114808eb9770443e4d
	https://git.kernel.org/stable/c/0c863cab0e9173f8b6c7bc328bee3b8625f131b5
	https://git.kernel.org/stable/c/e96fddb32931d007db12b1fce9b5e8e4c080401b