Linux Kernel Deadlock Vulnerability in Cadence MACB Driver

A deadlock vulnerability has been identified in the Cadence MACB driver of the Linux kernel. This issue arises when the THALT signal is set high, causing the TGO signal to remain high as well. In this state, jiffies are not updated due to interrupts being disabled, leading to a perpetual loop and a deadlock condition. This issue was observed on a sama5d4 device, which became unresponsive for several days. The deadlock has been resolved by replacing jiffies with retries, ensuring that the timeout functions correctly and eliminating the deadlock condition.

Impact

Exploitation of this vulnerability can lead to a system deadlock, causing the device to become unresponsive for an extended period.