CVE-2026-89485

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

lockd: pin next file across nlminspectfile lock-drop

nlmtraversefiles() pins the current file with f_count++ across

a mutexunlock for nlminspect_file(), but nothing pins the saved

next pointer.  A concurrent nlmreleasefile() can kfree the next

file during the unlock window, and the iterator dereferences freed

memory on the next loop step.

Pin both current and next before the lock-drop.  Advance by

swapping the pinned cursors at the end of each iteration so next

is always held alive across the unlock.

Always call nlmfilerelease() after dropping the iteration pin,

regardless of whether the file matched the predicate.  Use

nlmfileinuse(), which does a live walk of the inode lock list,

rather than the cached f_locks field, so skipped files that never

ran nlminspectfile() are evaluated correctly.

Because every file in a hash bucket is now pinned and released,

files skipped by the isfailoverfile predicate that have no

locks, blocks, shares, or external references are deleted during

traversal.  The old code never evaluated skipped files for

cleanup.  The new behavior is intentional: such files are stale

and should not persist in the table.