CVE-2025-40120
net: usb: asix: hold PM usage ref to avoid PM/MDIO + RTNL deadlock
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.
INFO
Published Date :
Nov. 12, 2025, 11:15 a.m.
Last Modified :
Nov. 12, 2025, 11:15 a.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Affected Products
The following products are affected by CVE-2025-40120
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Hold PM usage reference in ax88772_bind().
- Drop PM usage reference in unbind().
- Ensure runtime PM is active for the device.
- Avoid runtime PM autosuspend for AX88772*.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-40120.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-40120 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-40120
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-40120 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2025-40120 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Nov. 12, 2025
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/1534517300e12f2930b6ff477b8820ff658afd11 Added Reference https://git.kernel.org/stable/c/3d3c4cd5c62f24bb3cb4511b7a95df707635e00a Added Reference https://git.kernel.org/stable/c/3e96cd27ff1a004d84908c1b6cc68ac60913874e Added Reference https://git.kernel.org/stable/c/71a0ba7fdaf8d035426912a4ed7bf1738a81010c Added Reference https://git.kernel.org/stable/c/724a9db84188f80ef60b1f21cc7b4e9c84e0cb64 Added Reference https://git.kernel.org/stable/c/9d8bcaf6fae1bd82bc27ec09a2694497e6f6c4b4