# CVE-2025-40196

## Summary

- **CVE ID:** CVE-2025-40196
- **Severity:** UNKNOWN
- **CVSS Score:** 1.51
- **CWE:** N/A
- **Published:** Nov 12, 2025
- **Last Modified:** Sep 17, 2026

## Description

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

fs: quota: create dedicated workqueue for quota_release_work

There is a kernel panic due to WARN_ONCE when panic_on_warn is set.

This issue occurs when writeback is triggered due to sync call for an
opened file(ie, writeback reason is WB_REASON_SYNC). When f2fs balance
is needed at sync path, flush for quota_release_work is triggered.
By default quota_release_work is queued to "events_unbound" queue which
does not have WQ_MEM_RECLAIM flag. During f2fs balance "writeback"
workqueue tries to flush quota_release_work causing kernel panic due to
MEM_RECLAIM flag mismatch errors.

This patch creates dedicated workqueue with WQ_MEM_RECLAIM flag
for work quota_release_work.

------------[ cut here ]------------
WARNING: CPU: 4 PID: 14867 at kernel/workqueue.c:3721 check_flush_dependency+0x13c/0x148
Call trace:
 check_flush_dependency+0x13c/0x148
 __flush_work+0xd0/0x398
 flush_delayed_work+0x44/0x5c
 dquot_writeback_dquots+0x54/0x318
 f2fs_do_quota_sync+0xb8/0x1a8
 f2fs_write_checkpoint+0x3cc/0x99c
 f2fs_gc+0x190/0x750
 f2fs_balance_fs+0x110/0x168
 f2fs_write_single_data_page+0x474/0x7dc
 f2fs_write_data_pages+0x7d0/0xd0c
 do_writepages+0xe0/0x2f4
 __writeback_single_inode+0x44/0x4ac
 writeback_sb_inodes+0x30c/0x538
 wb_writeback+0xf4/0x440
 wb_workfn+0x128/0x5d4
 process_scheduled_works+0x1c4/0x45c
 worker_thread+0x32c/0x3e8
 kthread+0x11c/0x1b0
 ret_from_fork+0x10/0x20
Kernel panic - not syncing: kernel: panic_on_warn set ...

## Affected Products

- Linux — Linux (bcacb52a985f1b6d280f698a470b873dfe52728a)
- Linux — Linux (8ea87e34792258825d290f4dc5216276e91cb224)
- Linux — Linux (ac6f420291b3fee1113f21d612fa88b628afab5b)
- Linux — Linux (a5abba5e0e586e258ded3e798fe5f69c66fec198)
- Linux — Linux (6f3821acd7c3143145999248087de5fb4b48cf26)
- Linux — Linux (ab6cfcf8ed2c7496f55d020b65b1d8cd55d9a2cb)
- Linux — Linux (3e6ff207cd5bd924ad94cd1a7c633bcdac0ba1cb)
- Linux — Linux (6.13)
- Linux — Linux (0)
- Linux — Linux (6.6.114)
- Linux — Linux (6.12.54)
- Linux — Linux (6.17.4)
- Linux — Linux (6.18)
- Linux — Linux (6.6.64)
- Linux — Linux (6.12.4)
- Linux — Linux (5.4.287)
- Linux — Linux (5.10.231)
- Linux — Linux (5.15.174)
- Linux — Linux (6.1.120)
- Linux — Linux (6.1.178)

## References

- [CNA](https://git.kernel.org/stable/c/f846eacde280ecc3daedfe001580e3033565179e)
- [CNA](https://git.kernel.org/stable/c/f12039df1515d5daf7d92e586ece5cefeb39561b)
- [CNA](https://git.kernel.org/stable/c/8a09a62f0c8c6123c2f1864ed6d5f9eb144afaf0)
- [CNA](https://git.kernel.org/stable/c/72b7ceca857f38a8ca7c5629feffc63769638974)
- [CNA](https://git.kernel.org/stable/c/8df2eedd371a1c24ecc4283581299d7737dfcd06)
- [siemens-SADP](https://cert-portal.siemens.com/productcert/html/ssa-019113.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.19%
- **EPSS Percentile:** 9.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._