The bug causes a deadlock in the f2fs file system when a device is mounted with the gc_merge option. During normal write operations the kernel wakes the garbage‑collection thread and waits for it to finish. The GC thread, while performing out‑of‑place writes, recursively acquires a folio lock that is already held by the wait‑queue operation waiting for writeback to clear. The result is a self‑sustaining lock cycle that freezes the kernel, potentially rendering the affected system unresponsive. This lack of atomicity and proper lock ordering directly violates basic concurrency guarantees.

All Linux kernel releases that include the f2fs file system may be affected until the patch is applied. The vulnerability manifests when the fs is mounted with the gc_merge option, a feature often used for more aggressive garbage collection. Systems that rely on high I/O throughput or that frequently trigger background garbage collection are at greatest risk.

The severity is high due to the complete loss of system availability, but the CVSS score is not provided in the data. The EPSS score is not available and the issue is not listed in CISA’s KEV catalog, so publicly known exploitation attempts are currently unknown. The attack vector is likely local; an attacker must be able to influence the device that is mounted with the gc_merge option or corrupt the I/O timing sufficient to trigger the lock cycle. In the absence of a patch, the exploit does not require external network access, making systems that allow local users to mount f2fs filesystems the most vulnerable.