GHSA-R32M-FJ66-QF6P
Vulnerability from github – Published: 2026-09-11 21:31 – Updated: 2026-09-14 15:32In the Linux kernel, the following vulnerability has been resolved:
ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()
Patch series "ocfs2: cluster: o2hb_region_pin() fixes", v2.
This series fixes three related issues in o2hb_region_pin(), all are from the original implementation in commit: 58a3158a5d17 ("ocfs2/cluster: Pin/unpin o2hb regions"):
1) It is called with o2hb_live_lock (a spinlock) held, but the underlying configfs_depend_item() sleeps (takes inode rwsem and pins the filesystem). This triggers BUG under CONFIG_DEBUG_ATOMIC_SLEEP.
2) When called from the configfs drop_item callback, it creates a lock order inversion: parent inode_lock -> configfs root inode_lock, which can deadlock against subsystem unregistration paths taking root -> parent.
3) If pinning fails partway through o2hb_region_inc_user(), the o2hb_dependent_users counter is leaked and partially-pinned regions are never released, leaving heartbeat regions unprotected on subsequent mounts.
Patch 1 reworks o2hb_region_pin() to drop o2hb_live_lock across each sleeping configfs_depend_item() call, using a config_item reference to keep the region alive while unlocked.
Patch 2 adds a from_callback parameter to select configfs_depend_item_unlocked() when called from configfs context, avoiding the inode_lock nesting.
Patch 3 fixes the error path in o2hb_region_inc_user() to unpin and decrement the counter on failure.
This patch (of 3):
o2hb_region_pin() is always called with the o2hb_live_lock spinlock held (from o2hb_region_inc_user() and o2hb_heartbeat_group_drop_item()), but it calls o2nm_depend_item() -> configfs_depend_item(), which sleeps: it pins the configfs filesystem and takes the configfs root inode rwsem. Under CONFIG_DEBUG_ATOMIC_SLEEP this triggers:
BUG: sleeping function called from invalid context at kernel/locking/rwsem.c in_atomic(): 1, ... name: mount.ocfs2 down_write configfs_depend_item o2hb_region_pin o2hb_region_inc_user o2hb_register_callback dlm_register_domain_handlers ... ocfs2_dlm_init ocfs2_mount_volume ocfs2_fill_super
Rework o2hb_region_pin() to pin one region at a time with the lock dropped across the sleeping call: under o2hb_live_lock find the next eligible region and take a config_item reference to keep it alive, drop the lock, call o2nm_depend_item(), then retake the lock and record the pin. The config_item_put() is done with the lock released as well, since o2hb_region_release() also acquires o2hb_live_lock and can sleep. The region list may change while unlocked, so the scan restarts from the top after each pin. Local heartbeat still pins only the matching region; global heartbeat pins all eligible regions.
The unpin path is unaffected: configfs_undepend_item() only takes a spinlock and does not sleep.
{
"affected": [],
"aliases": [
"CVE-2026-89491"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-11T20:19:30Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nocfs2: cluster: don\u0027t 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 -\u003e configfs root\n inode_lock, which can deadlock against subsystem unregistration\n paths taking root -\u003e 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() -\u003e 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.",
"id": "GHSA-r32m-fj66-qf6p",
"modified": "2026-09-14T15:32:26Z",
"published": "2026-09-11T21:31:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89491"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0cbc2f20a6ea7b4a59efa9171b7c694cdd196507"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3b790774280a610f8bdbd5d4260a07345bcf8e04"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/470212a5eefabcc16b8e2f7fe2844b8737fe571c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/49002acc520c61002ad195894ac391c94317d3ba"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/4d64f8da82fb9e8dbd5aa9b64c9bb6ac0decea03"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/af09df89db9a68a1d76df0f75667998135bc8d65"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c9be4de77f97f383b750698e1517fd296041f4bb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ce035f208d68b812d83e5482980f2b1c88a9cd94"
}
],
"schema_version": "1.4.0",
"severity": []
}
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