---
id: CVE-2026-98537
title: 'workqueue: Fix NULL current_pwq deref in flush dependency check'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  workqueue: Fix NULL current_pwq deref in flush dependency check

  check_flush_dependency() uses current_wq_worker() to determine whether
  the caller is a workqueue worker…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    8ffececcb88262389b4f91fed0fe4884b68204bc
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    9bb739a5c5a570c28a62afb98e9326e2a49743c1
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    513121e69388604619ea8c0ee07e86a3d1b5b5dc
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    0c6b9b1e295aeff1132ac7aa738148cc65f06485
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    1dccf5dc2f8fe688270b261ca4216e03c6a1e674
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    f97e6d0572d1b39998e053732332bc3cfdd0b9aa
  - >-
    Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 <
    db6365ced4d5855e321f772b240c0e473bcfcdd5
  - Linux 4.5
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:18:05.028Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98537'
references:
  - url: 'https://git.kernel.org/stable/c/8ffececcb88262389b4f91fed0fe4884b68204bc'
  - url: 'https://git.kernel.org/stable/c/9bb739a5c5a570c28a62afb98e9326e2a49743c1'
  - url: 'https://git.kernel.org/stable/c/cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3'
  - url: 'https://git.kernel.org/stable/c/513121e69388604619ea8c0ee07e86a3d1b5b5dc'
  - url: 'https://git.kernel.org/stable/c/0c6b9b1e295aeff1132ac7aa738148cc65f06485'
  - url: 'https://git.kernel.org/stable/c/1dccf5dc2f8fe688270b261ca4216e03c6a1e674'
  - url: 'https://git.kernel.org/stable/c/f97e6d0572d1b39998e053732332bc3cfdd0b9aa'
  - url: 'https://git.kernel.org/stable/c/db6365ced4d5855e321f772b240c0e473bcfcdd5'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.278Z'
---

## Overview

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

workqueue: Fix NULL current_pwq deref in flush dependency check

check_flush_dependency() uses current_wq_worker() to determine whether
the caller is a workqueue worker and then dereferences worker->current_pwq
to test whether the current workqueue is WQ_MEM_RECLAIM.

current_wq_worker() only means that %current has PF_WQ_WORKER set. A
kworker can reach check_flush_dependency() while it is not executing a
work item. One such path is worker_thread() acting as the pool manager,
where create_worker() does GFP_KERNEL allocation and the allocation path
invokes the OOM notifier. In that state worker->current_pwq is NULL
because current_pwq is set only by process_one_work() and cleared again
after the work function returns.

[  416.760634][  T375] Call trace:
[  416.760638][  T375]  check_flush_dependency+0x80/0x120 (P)
[  416.760648][  T375]  __flush_work+0x98/0x224
[  416.760657][  T375]  flush_work+0x30/0x44
[  416.760665][  T375]  ...
[  416.760710][  T375]  blocking_notifier_call_chain+0x58/0xa0
[  416.760719][  T375]  out_of_memory+0xb4/0x458
[  416.760730][  T375]  __alloc_pages_may_oom+0x11c/0x1a8
[  416.760739][  T375]  __alloc_pages_slowpath+0x314/0x46c
[  416.760746][  T375]  __alloc_frozen_pages_noprof+0x110/0x1a4
[  416.760753][  T375]  new_slab+0x12c/0x484
[  416.760759][  T375]  ___slab_alloc+0x7a8/0xc7c
[  416.760765][  T375]  __slab_alloc+0x74/0xd8
[  416.760772][  T375]  __kmalloc_cache_node_noprof+0x2ac/0x304
[  416.760779][  T375]  alloc_worker+0x28/0x60
[  416.760785][  T375]  create_worker+0x4c/0x20c
[  416.760790][  T375]  worker_thread+0xe8/0x2b8
[  416.760796][  T375]  kthread+0x1a8/0x200
[  416.760805][  T375]  ret_from_fork+0x10/0x20

Guard the WQ_MEM_RECLAIM-worker warning with worker->current_pwq. If the
kworker is not currently executing a work item, there is no current
workqueue to diagnose with that warning. The PF_MEMALLOC warning is left
unchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target
is still reported.

## Affected

- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 8ffececcb88262389b4f91fed0fe4884b68204bc`
- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 9bb739a5c5a570c28a62afb98e9326e2a49743c1`
- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3`
- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 513121e69388604619ea8c0ee07e86a3d1b5b5dc`
- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 0c6b9b1e295aeff1132ac7aa738148cc65f06485`
- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < 1dccf5dc2f8fe688270b261ca4216e03c6a1e674`
- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < f97e6d0572d1b39998e053732332bc3cfdd0b9aa`
- `Linux >= fca839c00a12d682cb59b3b620d109a1d850b262 < db6365ced4d5855e321f772b240c0e473bcfcdd5`
- `Linux 4.5`

## Remediation

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