The following sequence of events happened to a freshly installed leap 42.2,
running on GCE:

1. > 3K packages are installed via zypper.
2. Bunch of system services are told to restart via systemctl restart,
including service "hmaint" and sshd.
3. The service "hmaint" is a simple script that waits a little while, then it
restarts a bunch of services and sshd.

During step 2, it is observed that systemctl restart command hangs on sshd.
When manually interrupted, "hmaint" is observed to be also calling systemctl
restart on sshd, and it is also hanging there.

>From there, all manual attempts at restarting sshd hang indefinitely.

Status of sshd is:
=================
* sshd.service - OpenSSH Daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; enabled; vendor
preset: disabled)
   Active: inactive (dead) since Mon 2016-11-21 19:44:53 CET; 25min ago
 Main PID: 1523 (code=exited, status=0/SUCCESS)

Nov 21 18:56:44 newhoward sshd[1914]: Accepted publickey for howard from
31.16.255.217 port 10537 ssh2: RSA
SHA256:2fyvKlwHg+gpOZsvvSm8yNkfcTdncUQPau44oSN4jVI
Nov 21 18:56:44 newhoward sshd[1914]: pam_unix(sshd:session): session opened
for user howard by (uid=0)
Nov 21 19:36:24 newhoward sshd[32175]: Did not receive identification string
from 113.108.21.16
Nov 21 19:44:53 newhoward systemd[1]: Stopping OpenSSH Daemon...
Nov 21 19:44:53 newhoward sshd[1523]: Received signal 15; terminating.
Nov 21 19:44:53 newhoward systemd[1]: Stopped OpenSSH Daemon.
Nov 21 19:48:45 newhoward systemd[1]: Stopped OpenSSH Daemon.
Nov 21 19:54:48 newhoward systemd[1]: Stopped OpenSSH Daemon.
Nov 21 19:54:56 newhoward systemd[1]: Stopped OpenSSH Daemon.
Nov 21 20:02:49 newhoward systemd[1]: Stopped OpenSSH Daemon.
==================

Status of hmaint is:
==================
* hmaint.service - System maintenance
   Loaded: loaded (/etc/systemd/system/hmaint.service; static; vendor preset:
disabled)
   Active: active (running) since Mon 2016-11-21 19:44:27 CET; 26min ago
 Main PID: 6570 (bash)
   CGroup: /system.slice/hmaint.service
           |- 6570 /bin/bash /hg/script/hmaint-invoke.sh
           |- 6577 bash /hg/script/hmaint.sh
           |- 6578 tee /tmp/hmaint.log
           `-13412 systemctl restart -f sshd.service

Nov 21 19:47:59 newhoward bash[6570]: chown: cannot access '/enc-home': No such
file or directory
Nov 21 19:47:59 newhoward bash[6570]: chmod: cannot access '/enc-home': No such
file or directory
Nov 21 19:47:59 newhoward bash[6570]: chown: cannot access '/home/howard-enc':
No such file or directory
Nov 21 19:47:59 newhoward bash[6570]: find: '/home/howard-enc': No such file or
directory
Nov 21 19:47:59 newhoward bash[6570]: find: '/home/howard-enc': No such file or
directory
Nov 21 19:48:19 newhoward systemd[1]: Started System maintenance.
Nov 21 19:48:23 newhoward bash[6570]: named.service is not a native service,
redirecting to systemd-sysv-install
Nov 21 19:48:23 newhoward bash[6570]: Executing
/usr/lib/systemd/systemd-sysv-install enable named
Nov 21 19:48:42 newhoward bash[6570]: Synchronizing state of postfix.service
with SysV init with /usr/lib/systemd/systemd-sysv-install...
Nov 21 19:48:42 newhoward bash[6570]: Executing
/usr/lib/systemd/systemd-sysv-install enable postfix
====================

Latest system journal entries are:
=====================
Nov 21 19:48:43 newhoward postfix/master[13358]: daemon started -- version
2.11.8, configuration /etc/postfix
Nov 21 19:48:43 newhoward systemd[1]: Started Postfix Mail Transport Agent.
Nov 21 19:48:45 newhoward systemd[1]: Reloading.
Nov 21 19:48:45 newhoward systemd[1]: nss-lookup.target: Dependency
Before=nss-lookup.target dropped
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/novnc-howard.service is marked world-inaccessible. This has
no effect as configuration data is accessible via APIs without restrictions.
Proceeding
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/hmaint.timer is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding anyway.
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/hmaint.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding anywa
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/openvpn@.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding any
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/openvpn@.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding any
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/openvpn@.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding any
Nov 21 19:48:45 newhoward systemd[1]: Reloading.
Nov 21 19:48:45 newhoward systemd[1]: nss-lookup.target: Dependency
Before=nss-lookup.target dropped
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/novnc-howard.service is marked world-inaccessible. This has
no effect as configuration data is accessible via APIs without restrictions.
Proceeding
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/hmaint.timer is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding anyway.
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/hmaint.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding anywa
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/openvpn@.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding any
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/openvpn@.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding any
Nov 21 19:48:45 newhoward systemd[1]: Configuration file
/etc/systemd/system/openvpn@.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding any
Nov 21 19:48:45 newhoward systemd[1]: Stopped OpenSSH Daemon.
Nov 21 19:54:19 newhoward systemd[1]: Configuration file
/etc/systemd/system/hmaint.service is marked world-inaccessible. This has no
effect as configuration data is accessible via APIs without restrictions.
Proceeding anywa
Nov 21 19:54:48 newhoward systemd[1]: Stopped OpenSSH Daemon.
Nov 21 19:54:56 newhoward systemd[1]: Stopped OpenSSH Daemon.
Nov 21 20:00:01 newhoward cron[13428]: pam_unix(crond:session): session opened
for user root by (uid=0)
Nov 21 20:00:01 newhoward kernel: audit_printk_skb: 366 callbacks suppressed
Nov 21 20:00:01 newhoward kernel: audit: type=1101 audit(1479754801.163:854):
pid=13428 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:accounting
grantors=pam_listfile acct="root" exe="/usr/sbin/cron" hostname=? addr=? ter
Nov 21 20:00:01 newhoward kernel: audit: type=1103 audit(1479754801.163:855):
pid=13428 uid=0 auid=4294967295 ses=4294967295 msg='op=PAM:setcred
grantors=pam_rootok acct="root" exe="/usr/sbin/cron" hostname=? addr=? terminal
Nov 21 20:00:01 newhoward kernel: audit: type=1006 audit(1479754801.163:856):
pid=13428 uid=0 old-auid=4294967295 auid=0 old-ses=4294967295 ses=8 res=1
Nov 21 20:00:01 newhoward systemd[1]: Started Session 8 of user root.
Nov 21 20:00:01 newhoward kernel: audit: type=1105 audit(1479754801.207:857):
pid=13428 uid=0 auid=0 ses=8 msg='op=PAM:session_open
grantors=pam_loginuid,pam_limits,pam_unix,pam_umask,pam_systemd,pam_gnome_keyring,pam_env
ac
Nov 21 20:00:01 newhoward kernel: audit: type=1110 audit(1479754801.207:858):
pid=13428 uid=0 auid=0 ses=8 msg='op=PAM:setcred grantors=pam_rootok
acct="root" exe="/usr/sbin/cron" hostname=? addr=? terminal=cron res=success'
Nov 21 20:00:01 newhoward CRON[13428]: pam_unix(crond:session): session closed
for user root
Nov 21 20:00:01 newhoward kernel: audit: type=1104 audit(1479754801.347:859):
pid=13428 uid=0 auid=0 ses=8 msg='op=PAM:setcred grantors=pam_rootok
acct="root" exe="/usr/sbin/cron" hostname=? addr=? terminal=cron res=success'
Nov 21 20:00:01 newhoward kernel: audit: type=1106 audit(1479754801.351:860):
pid=13428 uid=0 auid=0 ses=8 msg='op=PAM:session_close
grantors=pam_loginuid,pam_limits,pam_unix,pam_umask,pam_systemd,pam_gnome_keyring,pam_env
a
Nov 21 20:02:49 newhoward systemd[1]: Stopped OpenSSH Daemon.