# 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.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **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:** Yes
- **Published:** 16 Dec 2025
- **Updated:** 5 Aug 2026
- **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

## 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.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68168 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2025-68168 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-68168/ (Markdown: https://insights.sbomify.com/CVE-2025-68168/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68168
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68168
- OSV: https://osv.dev/vulnerability/CVE-2025-68168

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68168/
Summaries are generated and may contain mistakes; the official description above is the record.