Linux Kernel Quota Workqueue Mismanagement Leading to Kernel Panic

A vulnerability in the Linux kernel's quota management system can cause a kernel panic. This issue arises when the writeback process is initiated for an open file, triggering a synchronization that requires balancing the file system. During this balance, the workqueue responsible for releasing quota data is flushed. However, the default queue used for this work does not support memory reclamation, leading to a mismatch error and a subsequent kernel panic. The vulnerability affects the Linux kernel stable tree.

Impact

The vulnerability causes a kernel panic, disrupting system operations and potentially leading to a denial of service.

Reproduction

The vulnerability can be reproduced by opening a file and triggering a synchronization writeback. This can be done by performing actions that require data to be written back to the file system, such as modifying a file or using certain file management commands that initiate a sync. Once the writeback is in progress, the f2fs file system balance process will attempt to flush the quota release work, causing the kernel panic due to the memory reclamation flag mismatch.

Remediation

The vulnerability has been addressed in the Linux kernel. Users should upgrade to the latest version that includes the patch.