Subject: CVE-2024-49915: drm/amd/display: Add NULL check for clk_mgr in dcn32_init_hw

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

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

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

drm/amd/display: Add NULL check for clk_mgr in dcn32_init_hw

This commit addresses a potential null pointer dereference issue in the
`dcn32_init_hw` function. The issue could occur when `dc->clk_mgr` is
null.

The fix adds a check to ensure `dc->clk_mgr` is not null before
accessing its functions. This prevents a potential null pointer
dereference.

Reported by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn32/dcn32_hwseq.c:961 dcn32_init_hw() error: we previously assumed 'dc->clk_mgr' could be null (see line 782)

The Linux kernel CVE team has assigned CVE-2024-49915 to this issue.

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

	Fixed in 6.10.14 with commit f0454b3cb058
	Fixed in 6.11.3 with commit 7d1854c86d02
	Fixed in 6.12-rc1 with commit c395fd47d156

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-2024-49915
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/dcn32/dcn32_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/f0454b3cb0584a6bf275aeb49be61a760fd546a2
	https://git.kernel.org/stable/c/7d1854c86d02cea8f8a0c0ca05f4ab14292baf3d
	https://git.kernel.org/stable/c/c395fd47d1565bd67671f45cca281b3acc2c31ef