Comment 16 for bug 1821255

Confirmed fix in bionic, according to test case:

ubuntu@bionic:~$ ./deploy-tgt.sh

ubuntu@bionic:~$ dpkg -l | grep open-iscsi
ii open-iscsi 2.0.874-5ubuntu2.7 amd64 iSCSI initiator tools

ubuntu@bionic:~$ sudo pkill iscsid

ubuntu@bionic:~$ sudo systemctl stop iscsid
Warning: Stopping iscsid.service, but it can still be activated by:
  iscsid.socket

ubuntu@bionic:~$

The systemctl stop command doesn't hang anymore, and the service can be restarted normally.