---
id: CVE-2026-90276
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  md/md-llbitmap: stop daemon timer rearm on destroy

  llbitmap_destroy() deletes pending_timer before flushing
  md_llbitmap_io_wq
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  md/md-llbitmap: stop daemon timer rearm on destroy

  llbitmap_destroy() deletes pending_timer before flushing
  md_llbitmap_io_wq. However, daemon_work can still be queued…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5ab829f1971dc99f2aac10846c378e67fc875abc <
    c55aa6c17f019b6296952d336939891efa084c06
  - >-
    Linux >= 5ab829f1971dc99f2aac10846c378e67fc875abc <
    bb7f92d58fca9a9f06f3f51a82481c5f0bbbd46c
  - >-
    Linux >= 5ab829f1971dc99f2aac10846c378e67fc875abc <
    5553d64e01d9a995be6c3de38501c6dd4ceede3b
  - Linux 6.18
published: '2026-09-17'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T17:17:24.247'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90276'
references:
  - url: 'https://git.kernel.org/stable/c/5553d64e01d9a995be6c3de38501c6dd4ceede3b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/bb7f92d58fca9a9f06f3f51a82481c5f0bbbd46c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/c55aa6c17f019b6296952d336939891efa084c06'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-17T16:21:47.836Z'
epss: 0.00206
epssPercentile: 0.09468
---

## Overview

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

md/md-llbitmap: stop daemon timer rearm on destroy

llbitmap_destroy() deletes pending_timer before flushing
md_llbitmap_io_wq. However, daemon_work can still be queued or running
after the timer has been deleted, and the daemon path can arm
pending_timer again when it finds dirty chunks that are not ready to
flush yet.

If that happens during teardown, pending_timer can remain armed after
llbitmap is freed and later dereference freed memory.

Add a BITMAP_SHUTDOWN bit to llbitmap->flags, set it before deleting
the timer, and make the timer and daemon paths stop queueing or rearming
work once teardown starts. Cancel daemon_work before flushing the shared
workqueue so no already queued daemon instance can race with the free.
Use timer_shutdown_sync() so a daemon instance that passed the shutdown
check before teardown cannot rearm the timer afterward.

BITMAP_SHUTDOWN is a runtime-only state. Mask it out when reading and
updating the llbitmap superblock so the shutdown state is never loaded
from disk or persisted to disk.

## Remediation

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