Tom Chung

A vulnerability in the Linux kernel has been resolved. The issue was related to a commit that used the HW lock manager for PSR1, which could cause a system hang when connecting with two eDP panels.

Name of the Vulnerable Software and Affected Versions: Linux kernel versions prior to 6.6.58 Description: A flaw in the Linux kernel has been identified, causing the system to hang when resuming with a Thunderbolt (TBT) monitor. This issue occurs because the TBT monitor HPD is triggered during the resume procedure, calling the `drm client modeset probe()` function while `struct drm connector connector->dev->master` is NULL, which messes up the pipe topology after resume. Recommendations: For Linux kernel versions prior to 6.6.58, update to version 6.6.58 or later to resolve the issue. As a temporary workaround, consider skipping the TBT monitor HPD during the resume procedure. Restrict access to the `drm client modeset probe()` function to minimize the risk of exploitation until the issue is resolved.

The issue is related to a bounds check in the Linux kernel's drm/amd/display component, specifically for dcn35 DcfClocks. The problem arises because `NumFclkLevelsEnabled` is used instead of the designated `NumDcfClkLevelsEnabled` for the bounds check, potentially causing an array index out-of-bounds access.