Linux Kernel Livelock and Starvation Vulnerability in Memory Migration

A livelock and starvation vulnerability has been identified in the Linux kernel's memory migration process. This issue arises when the 'hmm_range_fault()' function fails to acquire a lock on a device-private folio for migration, causing the function to spin indefinitely. If the process holding the lock is waiting for a work item to complete on the same CPU, that work item can be starved, leading to an unresolved livelock situation. This vulnerability affects the Linux kernel stable tree and was introduced in version 6.15.

Impact

Exploitation of this vulnerability can cause a livelock situation, where a process is stuck in a loop and unable to make progress, effectively wasting CPU resources and potentially leading to performance degradation.

Reproduction

The vulnerability can be reproduced by running the 'xe_exec_system_allocator' IGT test, which triggers the conditions that cause the livelock and starvation problem during the memory migration process.

Remediation

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