If you have a single user with a problem pid, or simply kill a process is not enough and wish for whatever reason to remove/kill all PIDS for yourself (without booting yourself out in the process), a simple way to kill all active pids for a user is to do the following:
pkill –u username
pkill -u uid
And that’s all there is to it! The shutdown process that was hanging because of the zombie process mentioned above, immediately initiated after I executed the above kill.
To retrieve a user’s processes, use:
ps -fu username