Linux Kernel FCLK P-State Change Underflow Vulnerability in AMD Display Driver

A vulnerability in the Linux kernel's AMD display driver can lead to an underflow issue when changing the FCLK p-state. This problem arises because the FCLK p-state change watermark is currently based on a dummy latency value, rather than the actual FCLK p-state change latency, when UCLK p-state is not supported. The vulnerability affects the Linux kernel stable tree.

Impact

The vulnerability can cause an underflow in the FCLK p-state change process, potentially leading to incorrect performance states being set, which could disrupt proper graphics processing unit (GPU) performance management.

Reproduction

The vulnerability can be reproduced by using a graphics processing unit (GPU) that supports FCLK p-states but not UCLK p-states. When the FCLK p-state is changed, the system will incorrectly calculate the change based on a dummy latency, rather than the actual required latency, causing an underflow.

Remediation

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