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.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
EUVD |
EUVD-2025-25569 | 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. |
Ubuntu USN |
USN-7879-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7880-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-7879-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7879-4 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7934-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8028-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8028-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8031-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8028-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8028-4 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8028-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8031-2 | Linux kernel (GCP FIPS) vulnerabilities |
Ubuntu USN |
USN-8028-6 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-8031-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8052-1 | Linux kernel (Low Latency) vulnerabilities |
Ubuntu USN |
USN-8028-7 | Linux kernel (Low Latency NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8028-8 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-8052-2 | Linux kernel (Xilinx) vulnerabilities |
Ubuntu USN |
USN-8074-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8074-2 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8126-1 | Linux kernel (Azure) vulnerabilities |
Wed, 26 Nov 2025 17:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-362 CWE-476 |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Metrics |
cvssV3_1
|
cvssV3_1
|
Mon, 25 Aug 2025 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Sat, 23 Aug 2025 11:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Fri, 22 Aug 2025 16:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | pinmux: fix race causing mux_owner NULL with active mux_usecount | |
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:31:58.618Z
Reserved: 2025-04-16T04:51:24.029Z
Link: CVE-2025-38632
No data.
Status : Analyzed
Published: 2025-08-22T16:15:37.033
Modified: 2025-11-26T17:11:43.133
Link: CVE-2025-38632
OpenCVE Enrichment
Updated: 2025-08-23T10:55:22Z
EUVD
Ubuntu USN