CVE-2025-40196
Description
A workqueue configuration mismatch was found in the Linux kernel's filesystem quota subsystem during writeback operations. A local user can trigger this issue when f2fs filesystem balancing initiates quota writeback during sync operations, causing the writeback workqueue to flush quota_release_work from the events_unbound queue. Since events_unbound lacks the WQ_MEM_RECLAIM flag while the writeback queue has it, this flag mismatch triggers workqueue dependency warnings and causes kernel panic when panic_on_warn is enabled, resulting in denial of service.
Statement
Quota release work is queued to events_unbound (no WQ_MEM_RECLAIM flag) but gets flushed during f2fs writeback from a WQ_MEM_RECLAIM context. This flag mismatch triggers workqueue dependency checks that warn about potential deadlocks—if memory reclaim needs the work to complete but the work needs memory, deadlock could occur. Systems with panic_on_warn turn this warning into a hard panic. The fix creates a dedicated quota workqueue with the proper WQ_MEM_RECLAIM flag.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Other
Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
