---
id: CVE-2025-68319
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netconsole: Acquire su_mutex before navigating configs hierarchy

  There is a race between operations that iterate over the userdata
  cg_children list and concurrent add/…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  netconsole: Acquire su_mutex before navigating configs hierarchy

  There is a race between operations that iterate over the userdata
  cg_children list and concurrent add/…
severity: none
published: '2025-12-16'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T11:10:00.203'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-68319'
references:
  - url: 'https://git.kernel.org/stable/c/d7d2fcf7ae31471b4e08b7e448b8fd0ec2e06a1b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ff70aa7e8cf05745fdba7258952a8bedf33ea336'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00176
epssPercentile: 0.06505
ingestedAt: '2026-10-13T11:23:51.106Z'
---

## Overview

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

netconsole: Acquire su_mutex before navigating configs hierarchy

There is a race between operations that iterate over the userdata
cg_children list and concurrent add/remove of userdata items through
configfs. The update_userdata() function iterates over the
nt->userdata_group.cg_children list, and count_extradata_entries() also
iterates over this same list to count nodes.

Quoting from Documentation/filesystems/configfs.rst:
> A subsystem can navigate the cg_children list and the ci_parent pointer
> to see the tree created by the subsystem.  This can race with configfs'
> management of the hierarchy, so configfs uses the subsystem mutex to
> protect modifications.  Whenever a subsystem wants to navigate the
> hierarchy, it must do so under the protection of the subsystem
> mutex.

Without proper locking, if a userdata item is added or removed
concurrently while these functions are iterating, the list can be
accessed in an inconsistent state. For example, the list_for_each() loop
can reach a node that is being removed from the list by list_del_init()
which sets the nodes' .next pointer to point to itself, so the loop will
never end (or reach the WARN_ON_ONCE in update_userdata() ).

Fix this by holding the configfs subsystem mutex (su_mutex) during all
operations that iterate over cg_children.
This includes:
- userdatum_value_store() which calls update_userdata() to iterate over
  cg_children
- All sysdata_*_enabled_store() functions which call
  count_extradata_entries() to iterate over cg_children

The su_mutex must be acquired before dynamic_netconsole_mutex to avoid
potential lock ordering issues, as configfs operations may already hold
su_mutex when calling into our code.

## Remediation

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