CVE-2025-40120
Full vulnerability record from the local CVENow database.
Description
In the Linux kernel, the following vulnerability has been resolved: net: usb: asix: hold PM usage ref to avoid PM/MDIO + RTNL deadlock Prevent USB runtime PM (autosuspend) for AX88772* in bind. usbnet enables runtime PM (autosuspend) by default, so disabling it via the usb_driver flag is ineffective. On AX88772B, autosuspend shows no measurable power saving with current driver (no link partner, admin up/down). The ~0.453 W -> ~0.248 W drop on v6.1 comes from phylib powering the PHY off on admin-down, not from USB autosuspend. The real hazard is that with runtime PM enabled, ndo_open() (under RTNL) may synchronously trigger autoresume (usb_autopm_get_interface()) into asix_resume() while the USB PM lock is held. Resume paths then invoke phylink/phylib and MDIO, which also expect RTNL, leading to possible deadlocks or PM lock vs MDIO wake issues. To avoid this, keep the device runtime-PM active by taking a usage reference in ax88772_bind() and dropping it in unbind(). A non-zero PM usage count blocks runtime suspend regardless of userspace policy (.../power/control - pm_runtime_allow/forbid), making this approach robust against sysfs overrides. Holding a runtime-PM usage ref does not affect system-wide suspend; system sleep/resume callbacks continue to run as before.
Severity
Not scored
CVSS score
Not available
Vulnerability status
Deferred
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-11-12 11:15:41.430000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON
{
"id": "CVE-2025-40120",
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"published": "2025-11-12T11:15:41.430",
"lastModified": "2026-10-19T21:10:00.160",
"vulnStatus": "Deferred",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: usb: asix: hold PM usage ref to avoid PM/MDIO + RTNL deadlock\n\nPrevent USB runtime PM (autosuspend) for AX88772* in bind.\n\nusbnet enables runtime PM (autosuspend) by default, so disabling it via\nthe usb_driver flag is ineffective. On AX88772B, autosuspend shows no\nmeasurable power saving with current driver (no link partner, admin\nup/down). The ~0.453 W -> ~0.248 W drop on v6.1 comes from phylib powering\nthe PHY off on admin-down, not from USB autosuspend.\n\nThe real hazard is that with runtime PM enabled, ndo_open() (under RTNL)\nmay synchronously trigger autoresume (usb_autopm_get_interface()) into\nasix_resume() while the USB PM lock is held. Resume paths then invoke\nphylink/phylib and MDIO, which also expect RTNL, leading to possible\ndeadlocks or PM lock vs MDIO wake issues.\n\nTo avoid this, keep the device runtime-PM active by taking a usage\nreference in ax88772_bind() and dropping it in unbind(). A non-zero PM\nusage count blocks runtime suspend regardless of userspace policy\n(.../power/control - pm_runtime_allow/forbid), making this approach\nrobust against sysfs overrides.\n\nHolding a runtime-PM usage ref does not affect system-wide suspend;\nsystem sleep/resume callbacks continue to run as before."
},
{
"lang": "es",
"value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nnet: usb: asix: mantener la referencia de uso de PM para evitar el interbloqueo de PM/MDIO + RTNL\n\nEvitar la gestión de energía en tiempo de ejecución USB (suspensión automática) para AX88772* en la vinculación.\n\nusbnet habilita la gestión de energía en tiempo de ejecución (suspensión automática) por defecto, por lo que deshabilitarla a través del flag usb_driver es ineficaz. En el AX88772B, la suspensión automática no muestra un ahorro de energía medible con el controlador actual (sin compañero de enlace, admin arriba/abajo). La caída de ~0.453 W a ~0.248 W en la v6.1 proviene de phylib apagando el PHY en admin-down, no de la suspensión automática USB.\n\nEl verdadero peligro es que, con la gestión de energía en tiempo de ejecución habilitada, ndo_open() (bajo RTNL) puede activar sincrónicamente la reanudación automática (usb_autopm_get_interface()) en asix_resume() mientras el bloqueo de PM USB está mantenido. Las rutas de reanudación luego invocan phylink/phylib y MDIO, que también esperan RTNL, lo que lleva a posibles interbloqueos o problemas de bloqueo de PM vs activación de MDIO.\n\nPara evitar esto, se mantiene el dispositivo con la gestión de energía en tiempo de ejecución activa tomando una referencia de uso en ax88772_bind() y liberándola en unbind(). Un recuento de uso de PM distinto de cero bloquea la suspensión en tiempo de ejecución independientemente de la política del espacio de usuario (.../power/control - pm_runtime_allow/forbid), haciendo que este enfoque sea robusto contra las anulaciones de sysfs.\n\nMantener una referencia de uso de PM en tiempo de ejecución no afecta la suspensión a nivel de sistema; las devoluciones de llamada de suspensión/reanudación del sistema continúan ejecutándose como antes."
}
],
"affected": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"affectedData": [
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "unaffected",
"programFiles": [
"drivers/net/usb/asix_devices.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "4a2c7217cd5a87e85ceb761e307b030fe6db4805",
"lessThan": "71a0ba7fdaf8d035426912a4ed7bf1738a81010c",
"versionType": "git",
"status": "affected"
},
{
"version": "4a2c7217cd5a87e85ceb761e307b030fe6db4805",
"lessThan": "3e96cd27ff1a004d84908c1b6cc68ac60913874e",
"versionType": "git",
"status": "affected"
},
{
"version": "4a2c7217cd5a87e85ceb761e307b030fe6db4805",
"lessThan": "724a9db84188f80ef60b1f21cc7b4e9c84e0cb64",
"versionType": "git",
"status": "affected"
},
{
"version": "4a2c7217cd5a87e85ceb761e307b030fe6db4805",
"lessThan": "1534517300e12f2930b6ff477b8820ff658afd11",
"versionType": "git",
"status": "affected"
},
{
"version": "4a2c7217cd5a87e85ceb761e307b030fe6db4805",
"lessThan": "9d8bcaf6fae1bd82bc27ec09a2694497e6f6c4b4",
"versionType": "git",
"status": "affected"
},
{
"version": "4a2c7217cd5a87e85ceb761e307b030fe6db4805",
"lessThan": "3d3c4cd5c62f24bb3cb4511b7a95df707635e00a",
"versionType": "git",
"status": "affected"
}
]
},
{
"vendor": "Linux",
"product": "Linux",
"defaultStatus": "affected",
"programFiles": [
"drivers/net/usb/asix_devices.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"versions": [
{
"version": "5.14",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.14",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "5.15.195",
"lessThanOrEqual": "5.15.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.1.156",
"lessThanOrEqual": "6.1.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.6.112",
"lessThanOrEqual": "6.6.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.12.53",
"lessThanOrEqual": "6.12.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.17.3",
"lessThanOrEqual": "6.17.*",
"versionType": "semver",
"status": "unaffected"
},
{
"version": "6.18",
"lessThanOrEqual": "*",
"versionType": "original_commit_for_fix",
"status": "unaffected"
}
]
}
]
}
],
"metrics": {},
"references": [
{
"url": "https://git.kernel.org/stable/c/1534517300e12f2930b6ff477b8820ff658afd11",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/3d3c4cd5c62f24bb3cb4511b7a95df707635e00a",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/3e96cd27ff1a004d84908c1b6cc68ac60913874e",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/71a0ba7fdaf8d035426912a4ed7bf1738a81010c",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/724a9db84188f80ef60b1f21cc7b4e9c84e0cb64",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"url": "https://git.kernel.org/stable/c/9d8bcaf6fae1bd82bc27ec09a2694497e6f6c4b4",
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
]
}