cgconfig stop-start will cause system to hang during shutdown

This document (7017872) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 12
SUSE Linux Enterprise Server 12 Service Pack 1 (SLES 12 SP1)

Situation

When starting and then stopping cgconfig either with:

systemctl start/stop cgconfig.service

or

service cgconfig start/stop

a shutdown or reboot after (later) will hang.

# service cgconfig status

output shows:

cgconfig.service - LSB: Create and setup control group filesystem(s)
Loaded: loaded (/etc/init.d/cgconfig)
Active: inactive (dead) since Thu 2016-07-21 10:09:08 PDT; 6s ago
Process: 6630 ExecStop=/etc/init.d/cgconfig stop (code=exited, status=0/SUCCESS)
Process: 6551 ExecStart=/etc/init.d/cgconfig start (code=exited, status=6)
Jul 21 10:07:42 name systemd[1]: Starting LSB: Create and setup control group filesystem(s)...
Jul 21 10:07:42 name cgconfig[6551]: Starting service cgconfig/etc/cgconfig.conf is not configured..failed
Jul 21 10:07:42 name cgconfig[6551]: ..done
Jul 21 10:09:08 name systemd[1]: Stopping LSB: Create and setup control group filesystem(s)...
Jul 21 10:09:08 name cgconfig[6630]: Stopping service cgconfigcgclear failed with Device or resource busy
Jul 21 10:09:08 name cgconfig[6630]: ..done

Resolution

A future libcgroup1 update will include the patch to resolve the problem.
Customers affected by this issue can contact SUSE Technical Support to request a PTF (temporary fix).

Cause

cgclear which unloads the cgroup filesystem clears all hierarchies, umounts their controller (subsystems), including subgroups in the systemd hierarchy which as a result breaks systemd.

Disclaimer

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