Subject: CVE-2024-49914: drm/amd/display: Add null check for pipe_ctx->plane_state in dcn20_program_pipe

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

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

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

drm/amd/display: Add null check for pipe_ctx->plane_state in dcn20_program_pipe

This commit addresses a null pointer dereference issue in the
`dcn20_program_pipe` function. The issue could occur when
`pipe_ctx->plane_state` is null.

The fix adds a check to ensure `pipe_ctx->plane_state` is not null
before accessing. This prevents a null pointer dereference.

Reported by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn20/dcn20_hwseq.c:1925 dcn20_program_pipe() error: we previously assumed 'pipe_ctx->plane_state' could be null (see line 1877)

The Linux kernel CVE team has assigned CVE-2024-49914 to this issue.

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

	Fixed in 6.11.3 with commit 65a6fee22d5c
	Fixed in 6.12-rc1 with commit 8e4ed3cf1642

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-2024-49914
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/dcn20/dcn20_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/65a6fee22d5cfa645cb05489892dc9cd3d142fc2
	https://git.kernel.org/stable/c/8e4ed3cf1642df0c4456443d865cff61a9598aa8