Subject: CVE-2024-49892: drm/amd/display: Initialize get_bytes_per_element's default to 1

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

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

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

drm/amd/display: Initialize get_bytes_per_element's default to 1

Variables, used as denominators and maybe not assigned to other values,
should not be 0. bytes_per_element_y & bytes_per_element_c are
initialized by get_bytes_per_element() which should never return 0.

This fixes 10 DIVIDE_BY_ZERO issues reported by Coverity.

The Linux kernel CVE team has assigned CVE-2024-49892 to this issue.

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

	Fixed in 5.10.227 with commit f921335123f6
	Fixed in 5.15.168 with commit 1f9f8186e239
	Fixed in 6.1.113 with commit a23d6029e730
	Fixed in 6.6.55 with commit c7630935d9a4
	Fixed in 6.10.14 with commit bc00d211da4f
	Fixed in 6.11.3 with commit 3334ab72cbba
	Fixed in 6.12-rc1 with commit 4067f4fa0423

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-2024-49892
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/dml/dcn20/display_rq_dlg_calc_20v2.c
	drivers/gpu/drm/amd/display/dc/dml/dcn21/display_rq_dlg_calc_21.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/f921335123f6620c3dce5c96fbb95f18524a021c
	https://git.kernel.org/stable/c/1f9f8186e239222f1c8d3dd73bf3bc6ae86c5e76
	https://git.kernel.org/stable/c/a23d6029e730f8a151b1a34afb169baac1274583
	https://git.kernel.org/stable/c/c7630935d9a4986e8c0ed91658a781b7a77d73f7
	https://git.kernel.org/stable/c/bc00d211da4ffad5314a2043b50bdc8ff8a33724
	https://git.kernel.org/stable/c/3334ab72cbba55a632f24579cd47c4a4e5e69cda
	https://git.kernel.org/stable/c/4067f4fa0423a89fb19a30b57231b384d77d2610