Comment 4 for bug 1705345

I hit this bug while trying to install a kernel upgrade (going from the default 4.13.0-16-generic to 4.13.8-041308, from the mainline PPA). I managed to get an strace from running "plymouth --ping". In the attached trace file, the hang happened on the last call to epoll_pwait.

I also tried attaching strace to plymouthd, but when I did that, it caused plymouthd to immediately exit (which in turn caused plymouth --ping to return). After that, subsequent runs of "plymouth --ping" returned immediately (getting ECONNREFUSED on the "/org/freedesktop/plymouthd" socket), and I haven't been able to reproduce the bug since.