Linux Kernel VC4 HDMI Deadlock Handling Vulnerability

A vulnerability in the Linux kernel's VC4 HDMI driver can lead to improper deadlock management. When the function 'vc4_hdmi_reset_link()' detects a deadlock, the driver fails to release all held locks before blocking until the contended lock is available. This mismanagement can cause issues in the locking context, as indicated by warnings when 'PROVE_LOCKING' is enabled. The vulnerability affects several Linux kernel versions, including 6.1.0-rc6.

Impact

The vulnerability can cause deadlocks in the HDMI handling, disrupting normal operations and potentially leading to performance issues or hangs.

Reproduction

The vulnerability can be reproduced by enabling 'PROVE_LOCKING' in the Linux kernel, which will expose the improper deadlock handling in the VC4 HDMI driver. When a deadlock occurs, the driver fails to drop all held locks, leading to a warning that can be observed in the system logs.

Remediation

Users can upgrade to the latest stable version of the Linux kernel, where this vulnerability has been addressed.