Leap 42.2 never finshes shutdown

I upgraded from 42.1 to 42.2. Or, rather, I tried. The upgrade failed miserably; the upgraded system quickly stopped its reboot with “Failed to load kernel.” I might have resurrected the upgrade with mkinitrd, but did not think of that at the time: Why would I? I performed a fresh installation. It only took two days to restore my system to its former glory. I am so glad I had backups of /etc and /usr.

Once a week I download and install updates. Then reboot. One would think a restart would be trivial. Not so any longer.

The shutdown gets to a wait state waiting for remotely mounted NFS volumes to unmount, and a couple of services. Apparently the OS never notices that the volumes have unmounted or the services have ended, and continues to wait. And wait. And wait. If the max-wait time is reached, IT ADDS 2 minutes to the max-wait every time it times out! Eventually the OS freezes at about 20 minutes.

It executes shutdown services in the wrong order. For instance, it stops the NMB/SMB daemon, then later waits for the SMB-mounted volumes to unmount. Same for NFS.

These message are repeated until it crashed. They started at 11:19, and crashed at 11:40. I suspect it is because the network had been shut down before unmounting.

Nov 25 11:20:36 sma-station14l kernel: CIFS VFS: Server sma-nas-02 has not responded in 120 seconds. Reconnecting...
Nov 25 11:22:21 sma-station14l kernel: nfs: server sma-nas-02 not responding, timed out
Nov 25 11:25:00 sma-station14l kernel: nfs: server sma-server3 not responding, timed out
Nov 25 11:26:54 sma-station14l systemd[1]: bkp.mount: Unmounting timed out. Stopping.
Nov 25 11:26:54 sma-station14l systemd[1]: w.mount: Unmounting timed out. Stopping.
Nov 25 11:26:54 sma-station14l systemd[1]: t.mount: Unmounting timed out. Stopping.
Nov 25 11:26:54 sma-station14l systemd[1]: u.mount: Unmounting timed out. Stopping.

Can anyone tell me where in the system these wait times are decided, and how to to change them?

Those daemons are not related to unmounting local filesystems (unless you attempt to loop mount from your own host). How are those filesystems mounted - from /etc/fstab or manually?

Those daemons are not related to unmounting local filesystems (unless  you attempt to loop mount from your own host).

Those are not local filesystems; they are served from a remote system. I would presume the OS would communicate with the remote server about disconnecting, a clean disconnect. Since the daemons have been shut down (and possibly the network adapter as well), the attempt would fail.

How are those filesystems  mounted - from /etc/fstab or manually?

The remote fs’ are mount from </etc/fstab>.