CVE-2025-68807

A race condition flaw was found in the Linux kernel's block layer writeback throttling (WBT) initialization. When enabling WBT during an I/O elevator change, a race with concurrent I/O submission can cause the WBT inflight counter to become negative. This leads to tasks hanging indefinitely in wbt_wait(), resulting in system unresponsiveness.

Triggering this issue requires changing the I/O scheduler (elevator) while the system is under I/O load. The hung tasks cause availability impact but do not allow privilege escalation or data corruption. Recovery typically requires a system reboot.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.