lockd: fix NULL dereference on lockowner allocation failure

Overview

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

lockd: fix NULL dereference on lockowner allocation failure

nlmclnt_locks_init_private() installs NLM file lock operations even when nlmclnt_find_lockowner() fails to allocate a lockowner. nlmclnt_proc() then returns -ENOMEM, but the VFS still tears down the partially initialized file_lock and calls locks_release_private().

That invokes nlmclnt_locks_release_private(), which dereferences fl->fl_u.nfs_fl.owner and crashes because the owner was never installed.

Clear fl_ops before attempting to initialize the NLM private state, and install the NLM lock operations only after a lockowner has been allocated successfully.

Affected

• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6db5af172ccc3223c8f730a9a4212f6427feee3e
• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 07adfbb3de7529f58ca708a97ead7fa4fdb71056
• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d662f7fc04fde305a27f304b3cd19b614d366839
• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 51af080ca4e553256c59a75a877b9b4fff828311
• Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4c7fc129db061c7daab841c4f3c342d894832362
• Linux 2.6.12

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

Vendor advisories

• Red Hat VEX · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-10-17 · vex