---
id: CVE-2025-38704
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access

  In the preparation stage of CPU online, if the corresponding
  the rdp's->nocb_cb_kthread does not e…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access

  In the preparation stage of CPU online, if the corresponding
  the rdp's->nocb_cb_kthread does not e…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: linux
product: linux_kernel
affected:
  - linux_kernel < 6.12.43
  - 'linux_kernel >= 6.13, < 6.15.11'
  - 'linux_kernel >= 6.16, < 6.16.2'
patched:
  - linux_kernel 6.16.2
published: '2025-09-04'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:17:57.020'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-38704'
references:
  - url: 'https://git.kernel.org/stable/c/1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1c951683a720b17c9ecaad1932bc95b29044611f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/3da45ec1e485a1a5ad31fe9ddd467c7ee5ae4ef9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9b5ec8e6b31755288a07b3abeeab8cd38e9d3c9d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b097ae798298885695c339d390b48b4e39619fa7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cce3d027227c69e85896af9fbc6fa9af5c68f067'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-019113.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-082556.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-457936.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00182
epssPercentile: 0.07722
ingestedAt: '2026-09-08T15:33:26.997Z'
---

## Overview

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

rcu/nocb: Fix possible invalid rdp's->nocb_cb_kthread pointer access

In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.

This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.

This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.

## Affected

- `linux_kernel < 6.12.43`
- `linux_kernel >= 6.13, < 6.15.11`
- `linux_kernel >= 6.16, < 6.16.2`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.16.2`