Linux Kernel DMA Engine IDXD Event Log Restoration Crash Vulnerability

A vulnerability in the Linux kernel's DMA engine IDXD driver can lead to a crash when the event log is disabled. This issue occurs if the hardware does not support error reporting to the event log, and an error requiring a Function Level Reset (FLR) is received. In such cases, the driver attempts to restore the event log, even if it was not previously allocated, leading to a potential crash. The problem has been addressed by ensuring that the driver only tries to free the event log if it was properly allocated.

Impact

The vulnerability can cause a system crash, disrupting normal operations and potentially leading to a denial of service.

Reproduction

The vulnerability can be reproduced by disabling the event log and then sending an error that triggers a Function Level Reset (FLR). The driver will attempt to restore the event log, causing a crash if the log was not allocated.

Remediation

Users can apply the latest patches available in the Linux kernel stable tree to address this vulnerability.