---
id: CVE-2026-97925
title: "In the Linux kernel, the following vulnerability has been resolved:\n\ntick/broadcast: Plug clockevents replacement race\n\n朱恺乾 reported and decoded the following race condition when a broadcast\ndevice is replaced:\n\nCPUA\t\t\t\t\tCPUB\n __tick_bro…"
summary: "In the Linux kernel, the following vulnerability has been resolved:\n\ntick/broadcast: Plug clockevents replacement race\n\n朱恺乾 reported and decoded the following race condition when a broadcast\ndevice is replaced:\n\nCPUA\t\t\t\t\tCPUB\n __tick_bro…"
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-366
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= f8381cba04ba8173fd5a2b8e5cd8b3290ee13a98 <
    338d6859cd1580617807290f6d7e92b1662d4695
  - >-
    Linux >= f8381cba04ba8173fd5a2b8e5cd8b3290ee13a98 <
    757aa9f548c18b96da1d56d11f65be8188a16d59
  - >-
    Linux >= f8381cba04ba8173fd5a2b8e5cd8b3290ee13a98 <
    3da55616db2b6b7d9caa3b7ff1e8983224e0ed52
  - >-
    Linux >= f8381cba04ba8173fd5a2b8e5cd8b3290ee13a98 <
    3525b94b2f258e0b99d1ee5a82a80b51bc1cc818
  - >-
    Linux >= f8381cba04ba8173fd5a2b8e5cd8b3290ee13a98 <
    292b7a8ed84032cfdfc9076a690360f7d3f640d4
  - >-
    Linux >= f8381cba04ba8173fd5a2b8e5cd8b3290ee13a98 <
    113a9796effe3376d2ec5aabcca1fef4fef4cd62
  - Linux 2.6.21
published: '2026-09-25'
updated: '2026-10-03'
sourceUpdated: '2026-10-03T11:18:10.290'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97925'
references:
  - url: 'https://git.kernel.org/stable/c/113a9796effe3376d2ec5aabcca1fef4fef4cd62'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/292b7a8ed84032cfdfc9076a690360f7d3f640d4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/338d6859cd1580617807290f6d7e92b1662d4695'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3525b94b2f258e0b99d1ee5a82a80b51bc1cc818'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3da55616db2b6b7d9caa3b7ff1e8983224e0ed52'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/757aa9f548c18b96da1d56d11f65be8188a16d59'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97925.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-97925'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2541083'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-97925'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97925'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97925.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00206
epssPercentile: 0.10511
cvssSource: vendor
ingestedAt: '2026-09-25T11:06:38.887Z'
---

## Overview

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

tick/broadcast: Plug clockevents replacement race

朱恺乾 reported and decoded the following race condition when a broadcast
device is replaced:

CPUA					CPUB
 __tick_broadcast_oneshot_control()
   bc = tick_broadcast_device.evtdev;
					tick_install_broadcast_device(dev)
        				clockevents_exchange_device(cur, dev)
					   shutdown(cur);
					   detach(cur);
					   cur->handler = noop;
					   tick_broadcast_device.evtdev = dev;

  tick_broadcast_set_event(bc, next_event); <- FAIL: arms a detached device.

If the original broadcast device has a restricted interrupt affinity mask
and the last CPU in that mask goes offline then the BUG() in
tick_cleanup_dead_cpu() triggers because the clockevent device is not in
detached state.

The reason for this is that tick_install_broadcast_device() is not
serialized vs. tick broadcast operations.

The obvious cure is to serialize tick_install_broadcast_device() with
tick_broadcast_lock against a concurrent tick broadcast operation.

That requires to split clockevents_exchange_device() into two parts, one
which does the exchange, shutdown and detach operation and the other which
drops the module reference count. This is required because the module
reference cannot be dropped while holding tick_broadcast_lock.

Let clockevents_exchange_device() do both operations as before, but let the
broadcast device code take the two step approach and do the device
exchange under tick_broadcast_lock and drop the module reference count
after releasing it.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 7, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-10-17 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-97925.json)