{"id":"CVE-2025-40120","state":"PUBLISHED","title":"net: usb: asix: hold PM usage ref to avoid PM/MDIO + RTNL deadlock","description":"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.","publishedAt":"2025-11-12T10:23:18.726Z","updatedAt":"2026-05-11T21:43:02.326Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"71a0ba7fdaf8d035426912a4ed7bf1738a81010c","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"3e96cd27ff1a004d84908c1b6cc68ac60913874e","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"724a9db84188f80ef60b1f21cc7b4e9c84e0cb64","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"1534517300e12f2930b6ff477b8820ff658afd11","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"9d8bcaf6fae1bd82bc27ec09a2694497e6f6c4b4","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"3d3c4cd5c62f24bb3cb4511b7a95df707635e00a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/usb/asix_devices.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.14","versionType":"semver"},{"version":"5.15.195","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.156","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.112","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.53","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.3","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/usb/asix_devices.c"]}],"references":["https://git.kernel.org/stable/c/71a0ba7fdaf8d035426912a4ed7bf1738a81010c","https://git.kernel.org/stable/c/3e96cd27ff1a004d84908c1b6cc68ac60913874e","https://git.kernel.org/stable/c/724a9db84188f80ef60b1f21cc7b4e9c84e0cb64","https://git.kernel.org/stable/c/1534517300e12f2930b6ff477b8820ff658afd11","https://git.kernel.org/stable/c/9d8bcaf6fae1bd82bc27ec09a2694497e6f6c4b4","https://git.kernel.org/stable/c/3d3c4cd5c62f24bb3cb4511b7a95df707635e00a"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/40xxx/CVE-2025-40120.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-40120","state":"PUBLISHED","datePublished":"2025-11-12T10:23:18.726Z","dateUpdated":"2026-05-11T21:43:02.326Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T07:20:57.169Z"},"containers":{"cna":{"title":"net: usb: asix: hold PM usage ref to avoid PM/MDIO + RTNL deadlock","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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"71a0ba7fdaf8d035426912a4ed7bf1738a81010c","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"3e96cd27ff1a004d84908c1b6cc68ac60913874e","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"724a9db84188f80ef60b1f21cc7b4e9c84e0cb64","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"1534517300e12f2930b6ff477b8820ff658afd11","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"9d8bcaf6fae1bd82bc27ec09a2694497e6f6c4b4","versionType":"git"},{"version":"4a2c7217cd5a87e85ceb761e307b030fe6db4805","status":"affected","lessThan":"3d3c4cd5c62f24bb3cb4511b7a95df707635e00a","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/usb/asix_devices.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.14","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.14","versionType":"semver"},{"version":"5.15.195","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.156","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.112","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.53","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.3","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/usb/asix_devices.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/71a0ba7fdaf8d035426912a4ed7bf1738a81010c"},{"url":"https://git.kernel.org/stable/c/3e96cd27ff1a004d84908c1b6cc68ac60913874e"},{"url":"https://git.kernel.org/stable/c/724a9db84188f80ef60b1f21cc7b4e9c84e0cb64"},{"url":"https://git.kernel.org/stable/c/1534517300e12f2930b6ff477b8820ff658afd11"},{"url":"https://git.kernel.org/stable/c/9d8bcaf6fae1bd82bc27ec09a2694497e6f6c4b4"},{"url":"https://git.kernel.org/stable/c/3d3c4cd5c62f24bb3cb4511b7a95df707635e00a"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:43:02.326Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"5.15.195"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.1.156"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.6.112"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.12.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.17.3"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.14","versionEndExcluding":"6.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}