CVE-2022-50398

/// Technical description

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

drm/msm/dp: add atomic_check to bridge ops

DRM commit_tails() will disable downstream crtc/encoder/bridge if

both disable crtc is required and crtc->active is set before pushing

a new frame downstream.

There is a rare case that user space display manager issue an extra

screen update immediately followed by close DRM device while down

stream display interface is disabled. This extra screen update will

timeout due to the downstream interface is disabled but will cause

crtc->active be set. Hence the followed commit_tails() called by

drm_release() will pass the disable downstream crtc/encoder/bridge

conditions checking even downstream interface is disabled.

This cause the crash to happen at dp_bridge_disable() due to it trying

to access the main link register to push the idle pattern out while main

link clocks is disabled.

This patch adds atomic_check to prevent the extra frame will not

be pushed down if display interf

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References