CVE-2025-68168 jfs: fix uninitialized waitqueue in transaction manager
An uninitialized waitqueue in the JFS transaction manager causes a system crash when mounting read-only filesystems, leading to denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-68168?
CVE-2025-68168 is a high-severity vulnerability in Linux, published on 16 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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().
Which versions are affected by CVE-2025-68168?
How do I fix CVE-2025-68168?
Apply the vendor's patch.
Is CVE-2025-68168 being exploited?
There is no known exploitation of CVE-2025-68168 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2025-68168, DEBIAN-CVE-2025-68168, GHSA-35pf-3h4j-jg2m, ROOT-OS-UBUNTU-2204-CVE-2025-68168, ROOT-OS-UBUNTU-2404-CVE-2025-68168, UBUNTU-CVE-2025-68168.