hwmon: (occ) unregister sysfs devices outside occ lock

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80660
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 08:16:51 UTC
Updated2026-08-28 08:16:51 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: hwmon: (occ) unregister sysfs devices outside occ lock occ_active(false) and occ_shutdown() unregister sysfs-backed devices while occ->lock is held. hwmon_device_unregister() and sysfs_remove_group() can wait for active sysfs callbacks to drain, and those callbacks can enter the OCC update path and try to take occ->lock again. That gives the unregister paths the lock ordering occ->lock -> sysfs callback drain, while a callback has the opposite edge sysfs callback -> occ->lock. This issue was found by our static analysis tool and then manually reviewed against the current tree. The grounded PoC kept the real unregister and callback carrier: occ_shutdown() hwmon_device_unregister() occ_show_temp_1() occ_update_response() Lockdep reported the circular dependency with occ_shutdown() already holding the OCC mutex and hwmon_device_unregister() waiting on the sysfs side: WARNING: possible circular locking dependency detected ... (sysfs_lock) ... at: hwmon_device_unregister+0x12/0x30 [vuln_msv] ... (&test_occ.lock) ... at: occ_shutdown.constprop.0+0xe/0x40 [vuln_msv] occ_update_response.isra.0+0xb/0x20 [vuln_msv] occ_show_temp_1.constprop.0.isra.0+0x23/0x40 [vuln_msv] *** DEADLOCK *** Serialize hwmon registration and removal with a separate hwmon_lock. Under that lock, detach occ->hwmon and update occ->active while occ->lock is held so concurrent OCC state changes still see a stable state, then drop occ->lock before calling hwmon_device_unregister(). Remove the driver sysfs group before taking occ->lock in occ_shutdown(), so draining the driver attributes cannot wait while the OCC mutex is held. Also make OCC update callbacks return -ENODEV after deactivation, so callbacks that already passed sysfs active protection do not poll the hardware after teardown has detached the hwmon device.

Risk And Classification

EPSS: 0.001720000 probability, percentile 0.067740000 (date 2026-08-30)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 849b0156d9960da628a06756bb920d9571c15e66 2a4c80ff3571498ec6a916273304b6650026b1b0 git Not specified
CNA Linux Linux affected 849b0156d9960da628a06756bb920d9571c15e66 e7fd81e9fb1fe476d2131fec66c1138457810ed4 git Not specified
CNA Linux Linux affected 849b0156d9960da628a06756bb920d9571c15e66 2092952f22a7da98e76e84139ae202b1fc7ba899 git Not specified
CNA Linux Linux affected 849b0156d9960da628a06756bb920d9571c15e66 f0aad157576da199c146c1bb266442befa7912ca git Not specified
CNA Linux Linux affected 849b0156d9960da628a06756bb920d9571c15e66 7ee43ec8e6774774abbe9dc3027225e01bc964a5 git Not specified
CNA Linux Linux affected 849b0156d9960da628a06756bb920d9571c15e66 e31408734332b8cc611342cdaaab6ba492180156 git Not specified
CNA Linux Linux affected bc8a32726774286325b0cb0daab55b682cafc1ef git Not specified
CNA Linux Linux affected 5.15.216 5.16 semver Not specified
CNA Linux Linux affected 5.19 Not specified
CNA Linux Linux unaffected 5.19 semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/e31408734332b8cc611342cdaaab6ba492180156 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f0aad157576da199c146c1bb266442befa7912ca 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7ee43ec8e6774774abbe9dc3027225e01bc964a5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2a4c80ff3571498ec6a916273304b6650026b1b0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e7fd81e9fb1fe476d2131fec66c1138457810ed4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2092952f22a7da98e76e84139ae202b1fc7ba899 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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