I just tested plymouth --ping and it hangs again. Aborting and rerunning it with --debug gives the same output as you:
haster@schootbak3:~ $ plymouth --ping ^C
haster@schootbak3:~ $ plymouth --debug --ping [ply-event-loop.c:759] ply_event_loop_stop_watching_fd:stopping watching fd 6 [ply-event-loop.c:775] ply_event_loop_stop_watching_fd:removing destination for fd 6
I just tested plymouth --ping and it hangs again. Aborting and rerunning it with --debug gives the same output as you:
haster@schootbak3:~
$ plymouth --ping
^C
haster@schootbak3:~ loop.c: 759] ply_event_ loop_stop_ watching_ fd:stopping watching fd 6 loop.c: 775] ply_event_ loop_stop_ watching_ fd:removing destination for fd 6
$ plymouth --debug --ping
[ply-event-
[ply-event-