# CVE-2025-22127

## Summary

- **CVE ID:** CVE-2025-22127
- **Severity:** MEDIUM
- **CVSS Score:** 5.5 (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
- **CWE:** N/A
- **Published:** Apr 16, 2025
- **Last Modified:** Sep 7, 2026

## Description

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

f2fs: fix potential deadloop in prepare_compress_overwrite()

Jan Prusakowski reported a kernel hang issue as below:

When running xfstests on linux-next kernel (6.14.0-rc3, 6.12) I
encountered a problem in generic/475 test where fsstress process
gets blocked in __f2fs_write_data_pages() and the test hangs.
The options I used are:

MKFS_OPTIONS  -- -O compression -O extra_attr -O project_quota -O quota /dev/vdc
MOUNT_OPTIONS -- -o acl,user_xattr -o discard,compress_extension=* /dev/vdc /vdc

INFO: task kworker/u8:0:11 blocked for more than 122 seconds.
      Not tainted 6.14.0-rc3-xfstests-lockdep #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:0    state:D stack:0     pid:11    tgid:11    ppid:2      task_flags:0x4208160 flags:0x00004000
Workqueue: writeback wb_workfn (flush-253:0)
Call Trace:
 <TASK>
 __schedule+0x309/0x8e0
 schedule+0x3a/0x100
 schedule_preempt_disabled+0x15/0x30
 __mutex_lock+0x59a/0xdb0
 __f2fs_write_data_pages+0x3ac/0x400
 do_writepages+0xe8/0x290
 __writeback_single_inode+0x5c/0x360
 writeback_sb_inodes+0x22f/0x570
 wb_writeback+0xb0/0x410
 wb_do_writeback+0x47/0x2f0
 wb_workfn+0x5a/0x1c0
 process_one_work+0x223/0x5b0
 worker_thread+0x1d5/0x3c0
 kthread+0xfd/0x230
 ret_from_fork+0x31/0x50
 ret_from_fork_asm+0x1a/0x30
 </TASK>

The root cause is: once generic/475 starts toload error table to dm
device, f2fs_prepare_compress_overwrite() will loop reading compressed
cluster pages due to IO error, meanwhile it has held .writepages lock,
it can block all other writeback tasks.

Let's fix this issue w/ below changes:
- add f2fs_handle_page_eio() in prepare_compress_overwrite() to
detect IO error.
- detect cp_error earler in f2fs_read_multi_pages().

## Affected Products

- Linux — Linux (4c8ff7095bef64fc47e996a938f7d57f9e077da3)
- Linux — Linux (5.6)
- Linux — Linux (0)
- Linux — Linux (6.14.2)
- Linux — Linux (6.15)
- Linux — Linux (6.12.109)

## References

- [CNA](https://git.kernel.org/stable/c/7215cf8ef54bdc9082dffac4662416d54961e258)
- [CNA](https://git.kernel.org/stable/c/3147ee567dd9004a49826ddeaf0a4b12865d4409)
- [CNA](https://git.kernel.org/stable/c/7cd460bd9e7c6e6c30a33982603f65fb5deab1e4)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.14%
- **EPSS Percentile:** 4.2

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