---
id: CVE-2026-31598
title: 'ocfs2: fix possible deadlock between unlink and dio_end_io_write'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  ocfs2: fix possible deadlock between unlink and dio_end_io_write

  ocfs2_unlink takes orphan dir inode_lock first and then ip_alloc_sem,
  while in ocfs2_dio_end_io_write,…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    297d8d7bb6a2bf133d3a3636edbdf94101cbd719
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    32630dee18c6bb2175c8a865a474749492eaf19c
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    93f35419eb84d58820040642cb6e7528fe4aba7a
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    4b80b5a838a32437f2cae0662578bac216a2c51a
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    2b884d52273c60c298bd570163e8053657bbaff6
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    bc0fb5c7d54c78be43a536df0e20dee32adb27d3
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    f9fb1a7b635849322e1d7b7b6b26389778ec8e82
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    e049f7a9bd80b7319590789ea5e1c523d6339d91
  - >-
    Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 <
    b02da26a992db0c0e2559acbda0fc48d4a2fd337
  - Linux 4.6
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-16T15:11:06.751234Z'
published: '2026-04-24'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:16.438Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-31598'
references:
  - url: 'https://git.kernel.org/stable/c/297d8d7bb6a2bf133d3a3636edbdf94101cbd719'
  - url: 'https://git.kernel.org/stable/c/32630dee18c6bb2175c8a865a474749492eaf19c'
  - url: 'https://git.kernel.org/stable/c/93f35419eb84d58820040642cb6e7528fe4aba7a'
  - url: 'https://git.kernel.org/stable/c/4b80b5a838a32437f2cae0662578bac216a2c51a'
  - url: 'https://git.kernel.org/stable/c/2b884d52273c60c298bd570163e8053657bbaff6'
  - url: 'https://git.kernel.org/stable/c/bc0fb5c7d54c78be43a536df0e20dee32adb27d3'
  - url: 'https://git.kernel.org/stable/c/f9fb1a7b635849322e1d7b7b6b26389778ec8e82'
  - url: 'https://git.kernel.org/stable/c/e049f7a9bd80b7319590789ea5e1c523d6339d91'
  - url: 'https://git.kernel.org/stable/c/b02da26a992db0c0e2559acbda0fc48d4a2fd337'
tags:
  - cve.org
epss: 0.00435
epssPercentile: 0.36379
ingestedAt: '2026-10-16T17:24:46.663Z'
---

## Overview

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

ocfs2: fix possible deadlock between unlink and dio_end_io_write

ocfs2_unlink takes orphan dir inode_lock first and then ip_alloc_sem,
while in ocfs2_dio_end_io_write, it acquires these locks in reverse order.
This creates an ABBA lock ordering violation on lock classes
ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE] and
ocfs2_file_ip_alloc_sem_key.

Lock Chain #0 (orphan dir inode_lock -> ip_alloc_sem):
ocfs2_unlink
  ocfs2_prepare_orphan_dir
    ocfs2_lookup_lock_orphan_dir
      inode_lock(orphan_dir_inode) <- lock A
    __ocfs2_prepare_orphan_dir
      ocfs2_prepare_dir_for_insert
        ocfs2_extend_dir
	  ocfs2_expand_inline_dir
	    down_write(&oi->ip_alloc_sem) <- Lock B

Lock Chain #1 (ip_alloc_sem -> orphan dir inode_lock):
ocfs2_dio_end_io_write
  down_write(&oi->ip_alloc_sem) <- Lock B
  ocfs2_del_inode_from_orphan()
    inode_lock(orphan_dir_inode) <- Lock A

Deadlock Scenario:
  CPU0 (unlink)                     CPU1 (dio_end_io_write)
  ------                            ------
  inode_lock(orphan_dir_inode)
                                    down_write(ip_alloc_sem)
  down_write(ip_alloc_sem)
                                    inode_lock(orphan_dir_inode)

Since ip_alloc_sem is to protect allocation changes, which is unrelated
with operations in ocfs2_del_inode_from_orphan.  So move
ocfs2_del_inode_from_orphan out of ip_alloc_sem to fix the deadlock.

## Affected

- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < 297d8d7bb6a2bf133d3a3636edbdf94101cbd719`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < 32630dee18c6bb2175c8a865a474749492eaf19c`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < 93f35419eb84d58820040642cb6e7528fe4aba7a`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < 4b80b5a838a32437f2cae0662578bac216a2c51a`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < 2b884d52273c60c298bd570163e8053657bbaff6`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < bc0fb5c7d54c78be43a536df0e20dee32adb27d3`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < f9fb1a7b635849322e1d7b7b6b26389778ec8e82`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < e049f7a9bd80b7319590789ea5e1c523d6339d91`
- `Linux >= a86a72a4a4e0ec109a98e2737948864ed6794bf7 < b02da26a992db0c0e2559acbda0fc48d4a2fd337`
- `Linux 4.6`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.