# CVE-2026-80879: ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write

> A local attacker can trigger a circular locking dependency in the OCFS2 filesystem, causing a system deadlock and denial of service.

- **Severity:** Not scored
- **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:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** BELL-CVE-2026-80879, DEBIAN-CVE-2026-80879, GHSA-3265-4r84-rmmm, UBUNTU-CVE-2026-80879

## What is CVE-2026-80879?

CVE-2026-80879 is a vulnerability in Linux, published on 4 Sep 2026. 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:

ocfs2: fix circular locking dependency in ocfs2_dio_end_io_write

A circular locking dependency involves INODE_ALLOC_SYSTEM_INODE,
EXTENT_ALLOC_SYSTEM_INODE, and ORPHAN_DIR_SYSTEM_INODE.

1. ocfs2_mknod() acquires INODE_ALLOC then EXTENT_ALLOC.

2. ocfs2_dio_end_io_write() acquires EXTENT_ALLOC for unwritten
   extents, then ORPHAN_DIR via ocfs2_del_inode_from_orphan() while still
   holding EXTENT_ALLOC.

3. ocfs2_wipe_inode() acquires ORPHAN_DIR then INODE_ALLOC via
   ocfs2_remove_inode.

Break the cycle in ocfs2_dio_end_io_write() by freeing the allocation
contexts (releasing EXTENT_ALLOC) before acquiring ORPHAN_DIR.

WARNING: possible circular locking dependency detected
------------------------------------------------------
is trying to acquire lock:
ffff8881e78b33a0
(&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}, at:
ocfs2_evict_inode+0x1539/0x43b0 fs/ocfs2/inode.c:1299

but task is already holding lock:
ffff8881e78b4fa0
(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at:
ocfs2_evict_inode+0xe97/0x43b0 fs/ocfs2/inode.c:1299

the existing dependency chain (in reverse order) is:

-> #2 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}:
       inode_lock include/linux/fs.h:1029 [inline]
       ocfs2_del_inode_from_orphan+0x12e/0x7a0 fs/ocfs2/namei.c:2728
       ocfs2_dio_end_io+0xf9c/0x1370 fs/ocfs2/aops.c:2418
       dio_complete+0x25b/0x790 fs/direct-io.c:281

-> #1 (&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}:
       inode_lock include/linux/fs.h:1029 [inline]
       ocfs2_reserve_suballoc_bits+0x16d/0x4840 fs/ocfs2/suballoc.c:882
       ocfs2_reserve_new_metadata_blocks+0x415/0x9a0
       fs/ocfs2/suballoc.c:1078
       ocfs2_mknod+0x10f3/0x2260 fs/ocfs2/namei.c:351

-> #0 (&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]){+.+.}-{4:4}:
       __lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
       lock_acquire+0x106/0x350 kernel/locking/lockdep.c:5868
       down_write+0x96/0x200 kernel/locking/rwsem.c:1625
       inode_lock include/linux/fs.h:1029 [inline]
       ocfs2_remove_inode fs/ocfs2/inode.c:733 [inline]
       ocfs2_wipe_inode fs/ocfs2/inode.c:896 [inline]
       ocfs2_delete_inode fs/ocfs2/inode.c:1157 [inline]
       ocfs2_evict_inode+0x1539/0x43b0 fs/ocfs2/inode.c:1299

Chain exists of:
  &ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE] -->
  &ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE] -->
  &ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]);
                               lock(&ocfs2_sysfile_lock_key[EXTENT_ALLOC_SYSTEM_INODE]);
                               lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]);
  lock(&ocfs2_sysfile_lock_key[INODE_ALLOC_SYSTEM_INODE]);

 *** DEADLOCK ***

## Which versions are affected by CVE-2026-80879?


## How do I fix CVE-2026-80879?

Apply the vendor's patch.

## Is CVE-2026-80879 being exploited?

There is no known exploitation of CVE-2026-80879 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80879 and fix it if it is affected.

What it is: CVE-2026-80879 is a vulnerability in Linux, published on 4 Sep 2026. 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-2026-80879 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-2026-80879/ (Markdown: https://insights.sbomify.com/CVE-2026-80879/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80879
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80879
- OSV: https://osv.dev/vulnerability/CVE-2026-80879

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80879/
Summaries are generated and may contain mistakes; the official description above is the record.