fkie_cve-2025-38632
Vulnerability from fkie_nvd
Published
2025-08-22 16:15
Modified
2025-08-22 18:08
Severity ?
Summary
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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\npinmux: fix race causing mux_owner NULL with active mux_usecount\n\ncommit 5a3e85c3c397 (\"pinmux: Use sequential access to access\ndesc-\u003epinmux data\") tried to address the issue when two client of the\nsame gpio calls pinctrl_select_state() for the same functionality, was\nresulting in NULL pointer issue while accessing desc-\u003emux_owner.\nHowever, issue was not completely fixed due to the way it was handled\nand it can still result in the same NULL pointer.\n\nThe issue occurs due to the following interleaving:\n\n cpu0 (process A) cpu1 (process B)\n\n pin_request() { pin_free() {\n\n mutex_lock()\n desc-\u003emux_usecount--; //becomes 0\n ..\n mutex_unlock()\n\n mutex_lock(desc-\u003emux)\n desc-\u003emux_usecount++; // becomes 1\n desc-\u003emux_owner = owner;\n mutex_unlock(desc-\u003emux)\n\n mutex_lock(desc-\u003emux)\n desc-\u003emux_owner = NULL;\n mutex_unlock(desc-\u003emux)\n\nThis sequence leads to a state where the pin appears to be in use\n(`mux_usecount == 1`) but has no owner (`mux_owner == NULL`), which can\ncause NULL pointer on next pin_request on the same pin.\n\nEnsure that updates to mux_usecount and mux_owner are performed\natomically under the same lock. Only clear mux_owner when mux_usecount\nreaches zero and no new owner has been assigned."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: pinmux: correcci\u00f3n de la carrera que causaba que mux_owner fuera nulo con el commit 5a3e85c3c397 de mux_usecount activa (\"pinmux: Usar acceso secuencial para acceder a los datos de desc-\u0026gt;pinmux\"). Se intent\u00f3 solucionar el problema cuando dos clientes del mismo GPIO llamaban a pinctrl_select_state() para la misma funcionalidad, lo que provocaba un problema de puntero nulo al acceder a desc-\u0026gt;mux_owner. Sin embargo, el problema no se solucion\u00f3 por completo debido a la forma en que se gestion\u00f3 y a\u00fan puede resultar en el mismo puntero nulo. El problema se produce debido a la siguiente intercalaci\u00f3n: cpu0 (proceso A) cpu1 (proceso B) pin_request() { pin_free() { mutex_lock() desc-\u0026gt;mux_usecount--; //se convierte en 0 .. mutex_unlock() mutex_lock(desc-\u0026gt;mux) desc-\u0026gt;mux_usecount++; // se convierte en 1 desc-\u0026gt;mux_owner = owner; mutex_unlock(desc-\u0026gt;mux) mutex_lock(desc-\u0026gt;mux) desc-\u0026gt;mux_owner = NULL; mutex_unlock(desc-\u0026gt;mux) Esta secuencia lleva a un estado donde el pin parece estar en uso (`mux_usecount == 1`) pero no tiene propietario (`mux_owner == NULL`), lo que puede generar un puntero nulo en la siguiente solicitud de pin en el mismo pin. Aseg\u00farese de que las actualizaciones de mux_usecount y mux_owner se realicen autom\u00e1ticamente bajo el mismo bloqueo. Solo borre mux_owner cuando mux_usecount llegue a cero y no se haya asignado un nuevo propietario."
}
],
"id": "CVE-2025-38632",
"lastModified": "2025-08-22T18:08:51.663",
"metrics": {},
"published": "2025-08-22T16:15:37.033",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0b075c011032f88d1cfde3b45d6dcf08b44140eb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/22b585cbd67d14df3b91529d1b990661c300faa9"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9b2a3e7189028aa7c4d53a84364f2ea9fb209787"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9ea3f6b9a67be3476e331ce51cac316c2614a564"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/b7bd6e3971eb7f0e34d2fdce1b18b08094e0c804"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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