CVE-2026-89491 — ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()
In 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.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.2% (30-day exploitation probability)+2
The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
First 24 hours
Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.
- Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes, errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < 4d64f8da82fb9e8dbd5aa9b64c9bb6ac0decea03≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < 3b790774280a610f8bdbd5d4260a07345bcf8e04≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < 0cbc2f20a6ea7b4a59efa9171b7c694cdd196507≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < c9be4de77f97f383b750698e1517fd296041f4bb≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < 49002acc520c61002ad195894ac391c94317d3ba≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < ce035f208d68b812d83e5482980f2b1c88a9cd94≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < 470212a5eefabcc16b8e2f7fe2844b8737fe571c≥ 58a3158a5d17ddf4894db9e8ccaf92093ff8e42e and < af09df89db9a68a1d76df0f75667998135bc8d65 and 1 moreversion 2.6.38 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
EPSS over time FIRST
Oct 15, 2026 → Oct 22, 2026 · 7 reading(s) · max 0.22%
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Not enough vector or weakness data: use the affected application’s logs as a starting point.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- Affected products added · linux/linux
- Source status changed · → Received
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× References added · Oct 19, 2026 – Oct 19, 2026
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
10 on the record
- git.kernel.org/stable/c/0cbc2f20a6ea7b4a59efa9171b7c694cdd196507
- git.kernel.org/stable/c/ce035f208d68b812d83e5482980f2b1c88a9cd94
- git.kernel.org/stable/c/49002acc520c61002ad195894ac391c94317d3ba
- git.kernel.org/stable/c/af09df89db9a68a1d76df0f75667998135bc8d65
- git.kernel.org/stable/c/c9be4de77f97f383b750698e1517fd296041f4bb
- nvd.nist.gov/vuln/detail/CVE-2026-89491
- git.kernel.org/stable/c/4d64f8da82fb9e8dbd5aa9b64c9bb6ac0decea03
- github.com/advisories/GHSA-r32m-fj66-qf6p
- git.kernel.org/stable/c/470212a5eefabcc16b8e2f7fe2844b8737fe571c
- git.kernel.org/stable/c/3b790774280a610f8bdbd5d4260a07345bcf8e04
Elsewhere on this site
Related CVEs (same products)
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- Unknown CVE-2026-99079 net/mlx5e: Prevent stale XSK buffer release on refill retry 13h
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Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No CVSS score published by NVD, the CNA, CISA or GitHub so far.
- No fixed version, patch or mitigation documented.
- No CISA SSVC assessment.
- No CWE classification.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record
Text assembled only from the fields above — no additional claims.
What should defenders know first?
CVE-2026-89491 is "ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.22% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.
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