Linux Kernel DMUB Hardware Lock Mismanagement Vulnerability in AMD Display Driver

A vulnerability exists in the Linux kernel's AMD display driver, specifically within the management of the DMUB hardware lock during the hardware sequencer's fast path. This issue can cause the system to hang when the fast path is applied to certain ASICs lacking FAMS support. The vulnerability arises from an incorrect evaluation of when to use and release the DMUB lock, leading to potential deadlocks. The problem has been addressed by introducing a flag to properly manage the lock's usage and release, ensuring smoother operation on all supported ASICs.

Impact

The vulnerability could lead to system hangs or freezes, particularly when the fast path is used on ASICs without FAMS support, causing disruptions in the normal operation of the display driver.

Remediation

Users can upgrade to the latest version of the Linux kernel where this vulnerability has been fixed. The specific commit addressing this issue is available in the Linux kernel stable tree.