Race Condition Affecting kernel-modules package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.02% (5th percentile)

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  • Snyk IDSNYK-RHEL9-KERNELMODULES-12186399
  • published25 Aug 2025
  • disclosed22 Aug 2025

Introduced: 22 Aug 2025

NewCVE-2025-38632  (opens in a new tab)
CWE-362  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:9 kernel-modules.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-modules package and not the kernel-modules package as distributed by RHEL. See How to fix? for RHEL:9 relevant fixed versions and status.

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

pinmux: fix race causing mux_owner NULL with active mux_usecount

commit 5a3e85c3c397 ("pinmux: Use sequential access to access desc->pinmux data") tried to address the issue when two client of the same gpio calls pinctrl_select_state() for the same functionality, was resulting in NULL pointer issue while accessing desc->mux_owner. However, issue was not completely fixed due to the way it was handled and it can still result in the same NULL pointer.

The issue occurs due to the following interleaving:

 cpu0 (process A)                   cpu1 (process B)

pin_request() { pin_free() {

                                 mutex_lock()
                                 desc->mux_usecount--; //becomes 0
                                 ..
                                 mutex_unlock()

mutex_lock(desc->mux) desc->mux_usecount++; // becomes 1 desc->mux_owner = owner; mutex_unlock(desc->mux)

                                     mutex_lock(desc->mux)
                                     desc->mux_owner = NULL;
                                     mutex_unlock(desc->mux)

This sequence leads to a state where the pin appears to be in use (mux_usecount == 1) but has no owner (mux_owner == NULL), which can cause NULL pointer on next pin_request on the same pin.

Ensure that updates to mux_usecount and mux_owner are performed atomically under the same lock. Only clear mux_owner when mux_usecount reaches zero and no new owner has been assigned.

CVSS Base Scores

version 3.1