CVE-2023-52586: drm/msm/dpu: Add mutex lock in control vblank irq

CVE-2023-52586: drm/msm/dpu: Add mutex lock in control vblank irq

[Greg Kroah-Hartman]

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

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

drm/msm/dpu: Add mutex lock in control vblank irq

Add a mutex lock to control vblank irq to synchronize vblank
enable/disable operations happening from different threads to prevent
race conditions while registering/unregistering the vblank irq callback.

v4: -Removed vblank_ctl_lock from dpu_encoder_virt, so it is only a
    parameter of dpu_encoder_phys.
    -Switch from atomic refcnt to a simple int counter as mutex has
    now been added
v3: Mistakenly did not change wording in last version. It is done now.
v2: Slightly changed wording of commit message

Patchwork: https://patchwork.freedesktop.org/patch/571854/

The Linux kernel CVE team has assigned CVE-2023-52586 to this issue.


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

	Fixed in 6.7.4 with commit 14f109bf74dd
	Fixed in 6.8-rc1 with commit 45284ff733e4

Please see https://www.kernel.org or 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-2023-52586
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/msm/disp/dpu1/dpu_encoder.c
	drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
	drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_cmd.c
	drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.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/14f109bf74dd67e1d0469fed859c8e506b0df53f
	https://git.kernel.org/stable/c/45284ff733e4caf6c118aae5131eb7e7cf3eea5a