黑屏```-- Unit vncserver@:1.service has finished shutting down.Mar 17 14:51:45 octave.sh su : (to vnc_user) root on pts/0Mar 17 14:51:45 octave.sh su : pam_systemd(su-l:session): Cannot create session: Already running in a session or user sliceMar 17 14:51:45 octave.sh su : pam_unix(su-l:session): session opened for user vnc_user by root(uid=0)Mar 17 14:52:11 octave.sh polkitd : Registered Authentication Agent for unix-process:14567:1448779 (system bus name :1.2191 [/