CVE-2025-68168

In the Linux kernel, the following vulnerability has been resolved:

jfs: fix uninitialized waitqueue in transaction manager

The transaction manager initialization in txInit() was not properly initializing TxBlock[0].waitor waitqueue, causing a crash when txEnd(0) is called on read-only filesystems.

When a filesystem is mounted read-only, txBegin() returns tid=0 to indicate no transaction. However, txEnd(0) still gets called and tries to access TxBlock[0].waitor via tid_to_tblock(0), but this waitqueue was never initialized because the initialization loop started at index 1 instead of 0.

This causes a 'non-static key' lockdep warning and system crash: INFO: trying to register non-static key in txEnd

Fix by ensuring all transaction blocks including TxBlock[0] have their waitqueues properly initialized during txInit().

This vulnerability is rated as Moderate severity because exploitation requires local access to mount or process operations on a read-only JFS filesystem, limiting the impact to a denial of service rather than code execution or privilege escalation. Support for the legacy JFS filesystem is not enabled by default and is absent from modern Red Hat Enterprise Linux kernels. Consequently, default enterprise deployments are not exposed to this flaw.

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.