The gl command displays or removes group locks.
gl{-}
With no options, the monitor prints the status of the global group lock (with a G+ or a G-), and scans memory for any frames that are marked as locked. For each locked frame, the monitor displays the FID, the address of the buffer table entry, and all group lock information held in the frame itself.
To clear all group locks, type gl-.
To clear a specific group lock, type gl-{fid}.