{"id":"CVE-2026-80660","summary":"hwmon: (occ) unregister sysfs devices outside occ lock","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nhwmon: (occ) unregister sysfs devices outside occ lock\n\nocc_active(false) and occ_shutdown() unregister sysfs-backed devices while\nocc-\u003elock is held.  hwmon_device_unregister() and sysfs_remove_group() can\nwait for active sysfs callbacks to drain, and those callbacks can enter the\nOCC update path and try to take occ-\u003elock again.  That gives the unregister\npaths the lock ordering occ-\u003elock -\u003e sysfs callback drain, while a callback\nhas the opposite edge sysfs callback -\u003e occ-\u003elock.\n\nThis issue was found by our static analysis tool and then manually\nreviewed against the current tree.\n\nThe grounded PoC kept the real unregister and callback carrier:\n\n  occ_shutdown()\n  hwmon_device_unregister()\n  occ_show_temp_1()\n  occ_update_response()\n\nLockdep reported the circular dependency with occ_shutdown() already\nholding the OCC mutex and hwmon_device_unregister() waiting on the sysfs\nside:\n\n  WARNING: possible circular locking dependency detected\n  ... (sysfs_lock) ... at: hwmon_device_unregister+0x12/0x30 [vuln_msv]\n  ... (&test_occ.lock) ... at: occ_shutdown.constprop.0+0xe/0x40 [vuln_msv]\n  occ_update_response.isra.0+0xb/0x20 [vuln_msv]\n  occ_show_temp_1.constprop.0.isra.0+0x23/0x40 [vuln_msv]\n  *** DEADLOCK ***\n\nSerialize hwmon registration and removal with a separate hwmon_lock.\nUnder that lock, detach occ-\u003ehwmon and update occ-\u003eactive while occ-\u003elock\nis held so concurrent OCC state changes still see a stable state, then\ndrop occ-\u003elock before calling hwmon_device_unregister().  Remove the\ndriver sysfs group before taking occ-\u003elock in occ_shutdown(), so draining\nthe driver attributes cannot wait while the OCC mutex is held.  Also make\nOCC update callbacks return -ENODEV after deactivation, so callbacks that\nalready passed sysfs active protection do not poll the hardware after\nteardown has detached the hwmon device.","modified":"2026-10-28T02:58:39.498313210Z","published":"2026-08-28T06:49:04.992Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80660.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/2092952f22a7da98e76e84139ae202b1fc7ba899"},{"type":"WEB","url":"https://git.kernel.org/stable/c/2a4c80ff3571498ec6a916273304b6650026b1b0"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7ee43ec8e6774774abbe9dc3027225e01bc964a5"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e31408734332b8cc611342cdaaab6ba492180156"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e7fd81e9fb1fe476d2131fec66c1138457810ed4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f0aad157576da199c146c1bb266442befa7912ca"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80660.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80660"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"849b0156d9960da628a06756bb920d9571c15e66"},{"fixed":"2a4c80ff3571498ec6a916273304b6650026b1b0"},{"fixed":"e7fd81e9fb1fe476d2131fec66c1138457810ed4"},{"fixed":"2092952f22a7da98e76e84139ae202b1fc7ba899"},{"fixed":"f0aad157576da199c146c1bb266442befa7912ca"},{"fixed":"7ee43ec8e6774774abbe9dc3027225e01bc964a5"},{"fixed":"e31408734332b8cc611342cdaaab6ba492180156"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"5.15.216"},{"fixed":"5.16"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"bc8a32726774286325b0cb0daab55b682cafc1ef"}]}],"versions":["v5.15.223","v5.15.222","v5.15.221","v5.15.220","v5.15.219","v5.15.218","v5.15.217","v5.15.216"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80660.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.19.0"},{"fixed":"6.1.178"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.145"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.97"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.40"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.1.5"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-80660.json"}}],"schema_version":"1.9.2"}