CVE-2026-89491 — ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()

Affected: Linux

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_reg…

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CVE-2026-89491 — ocfs2: cluster: don't sleep while holding o2hb_live_lock in o2hb_region_pin()