---
id: CVE-2025-39745
title: 'rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels

  For built with CONFIG_PREEMPT_RT=y kernels, running rcutorture
  tests resulted in the following splat:…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= ec9d6356bfda69abe5f4767dd56c964127913233 <
    a85550267247cdf5e7499be00ea8e388ab014e50
  - >-
    Linux >= ec9d6356bfda69abe5f4767dd56c964127913233 <
    69c5ae0f441c2d72e8f48dc1e08464c172360c4c
  - >-
    Linux >= ec9d6356bfda69abe5f4767dd56c964127913233 <
    8d71351d88e478d3c4e945e3218e97ec677fd807
  - Linux 6.14
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T21:10:35.366400Z'
published: '2025-09-11'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T21:12:56.174Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2025-39745'
references:
  - url: 'https://git.kernel.org/stable/c/a85550267247cdf5e7499be00ea8e388ab014e50'
  - url: 'https://git.kernel.org/stable/c/69c5ae0f441c2d72e8f48dc1e08464c172360c4c'
  - url: 'https://git.kernel.org/stable/c/8d71351d88e478d3c4e945e3218e97ec677fd807'
tags:
  - cve.org
epss: 0.00157
epssPercentile: 0.04905
ingestedAt: '2026-11-05T22:38:32.023Z'
---

## Overview

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

rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels

For built with CONFIG_PREEMPT_RT=y kernels, running rcutorture
tests resulted in the following splat:

[   68.797425] rcutorture_one_extend_check during change: Current 0x1  To add 0x1  To remove 0x0  preempt_count() 0x0
[   68.797533] WARNING: CPU: 2 PID: 512 at kernel/rcu/rcutorture.c:1993 rcutorture_one_extend_check+0x419/0x560 [rcutorture]
[   68.797601] Call Trace:
[   68.797602]  <TASK>
[   68.797619]  ? lockdep_softirqs_off+0xa5/0x160
[   68.797631]  rcutorture_one_extend+0x18e/0xcc0 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[   68.797646]  ? local_clock+0x19/0x40
[   68.797659]  rcu_torture_one_read+0xf0/0x280 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[   68.797678]  ? __pfx_rcu_torture_one_read+0x10/0x10 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[   68.797804]  ? __pfx_rcu_torture_timer+0x10/0x10 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[   68.797815] rcu-torture: rcu_torture_reader task started
[   68.797824] rcu-torture: Creating rcu_torture_reader task
[   68.797824]  rcu_torture_reader+0x238/0x580 [rcutorture 2466dbd2ff34dbaa36049cb323a80c3306ac997c]
[   68.797836]  ? kvm_sched_clock_read+0x15/0x30

Disable BH does not change the SOFTIRQ corresponding bits in
preempt_count() for RT kernels, this commit therefore use
softirq_count() to check the if BH is disabled.

## Affected

- `Linux >= ec9d6356bfda69abe5f4767dd56c964127913233 < a85550267247cdf5e7499be00ea8e388ab014e50`
- `Linux >= ec9d6356bfda69abe5f4767dd56c964127913233 < 69c5ae0f441c2d72e8f48dc1e08464c172360c4c`
- `Linux >= ec9d6356bfda69abe5f4767dd56c964127913233 < 8d71351d88e478d3c4e945e3218e97ec677fd807`
- `Linux 6.14`

## Remediation

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