{"cve":"CVE-2026-89491","nvd":{"published":"2026-09-11T20:19:30.943","modified":"2026-10-19T09:17:42.920","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()\n\nPatch series \"ocfs2: cluster: o2hb_region_pin() fixes\", v2.\n\nThis series fixes three related issues in o2hb_region_pin(), all are from\nthe original implementation in commit: 58a3158a5d17 (\"ocfs2/cluster:\nPin/unpin o2hb regions\"):\n\n1) It is called with o2hb_live_lock (a spinlock) held, but the\n   underlying configfs_depend_item() sleeps (takes inode rwsem and\n   pins the filesystem).  This triggers BUG under\n   CONFIG_DEBUG_ATOMIC_SLEEP.\n\n2) When called from the configfs drop_item callback, it creates a\n   lock order inversion: parent inode_lock -> configfs root\n   inode_lock, which can deadlock against subsystem unregistration\n   paths taking root -> parent.\n\n3) If pinning fails partway through o2hb_region_inc_user(), the\n   o2hb_dependent_users counter is leaked and partially-pinned\n   regions are never released, leaving heartbeat regions\n   unprotected on subsequent mounts.\n\nPatch 1 reworks o2hb_region_pin() to drop o2hb_live_lock across each\nsleeping configfs_depend_item() call, using a config_item reference to\nkeep the region alive while unlocked.\n\nPatch 2 adds a from_callback parameter to select\nconfigfs_depend_item_unlocked() when called from configfs context,\navoiding the inode_lock nesting.\n\nPatch 3 fixes the error path in o2hb_region_inc_user() to unpin and\ndecrement the counter on failure.\n\n\nThis patch (of 3):\n\no2hb_region_pin() is always called with the o2hb_live_lock spinlock held\n(from o2hb_region_inc_user() and o2hb_heartbeat_group_drop_item()), but it\ncalls o2nm_depend_item() -> configfs_depend_item(), which sleeps: it pins\nthe configfs filesystem and takes the configfs root inode rwsem.  Under\nCONFIG_DEBUG_ATOMIC_SLEEP this triggers:\n\n  BUG: sleeping function called from invalid context at kernel/locking/rwsem.c\n  in_atomic(): 1, ... name: mount.ocfs2\n    down_write\n    configfs_depend_item\n    o2hb_region_pin\n    o2hb_region_inc_user\n    o2hb_register_callback\n    dlm_register_domain_handlers\n    ...\n    ocfs2_dlm_init\n    ocfs2_mount_volume\n    ocfs2_fill_super\n\nRework o2hb_region_pin() to pin one region at a time with the lock dropped\nacross the sleeping call: under o2hb_live_lock find the next eligible\nregion and take a config_item reference to keep it alive, drop the lock,\ncall o2nm_depend_item(), then retake the lock and record the pin.  The\nconfig_item_put() is done with the lock released as well, since\no2hb_region_release() also acquires o2hb_live_lock and can sleep.  The\nregion list may change while unlocked, so the scan restarts from the top\nafter each pin.  Local heartbeat still pins only the matching region;\nglobal heartbeat pins all eligible regions.\n\nThe unpin path is unaffected: configfs_undepend_item() only takes a\nspinlock and does not sleep.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/0cbc2f20a6ea7b4a59efa9171b7c694cdd196507","https://git.kernel.org/stable/c/3b790774280a610f8bdbd5d4260a07345bcf8e04","https://git.kernel.org/stable/c/470212a5eefabcc16b8e2f7fe2844b8737fe571c","https://git.kernel.org/stable/c/49002acc520c61002ad195894ac391c94317d3ba","https://git.kernel.org/stable/c/4d64f8da82fb9e8dbd5aa9b64c9bb6ac0decea03"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:53:43.293028046+00:00"},"epss":{"cve":"CVE-2026-89491","score":0.00216,"percentile":0.11942,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}