CVE-2026-92503

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix ABBA deadlock in ext4_xattr_inode_cache_find()

Syzbot/stress-ng reported an ABBA deadlock in ext4 when exercising

concurrent xattr workloads (using the ea_inode mount/format option).

The deadlock occurs between the running transaction and the eviction

thread:

- Task 1 (stress-ng): Holds a reference to a shared mbcache_entry (ce)

and calls ext4_xattr_inode_cache_find() -> ext4_iget() to retrieve

the corresponding EA inode. Since the EA inode is currently being

evicted, ext4_iget() blocks in __wait_on_freeing_inode() waiting for

eviction to complete.

- Task 2 (eviction thread): Currently evicting the same EA inode in

ext4_evict_ea_inode(). It calls mb_cache_entry_wait_unused(oe) which

blocks waiting for Task 1 to release the reference to the mbcache_entry.

To break this deadlock, implement a new ext4_iget() configuration flag

named EXT4_IGET_NOWAIT. When set, perform a non-blocking lookup of the

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References