CVE-2025-40196

  • Published: 2025-11-12T22:15:46.673

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 …

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How to fix CVE-2025-40196

CVE-2025-40196 is a unknown severity vulnerability affecting the affected product.

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 […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Exploit Difficulty Assessment

HARD
⏱️ Time to Exploit: > 4 hours
🛠️ Skills Required: Advanced security expertise
💰 Public Exploits: Rare or not public

Vulnerability Timeline

Nov 12, 2025
Vulnerability Published

CVE details first published to NVD database

Nov 12, 2025
Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.