It's still running but it hangs here:
--- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=31628, si_uid=0, si_status=0, si_utime=0, si_stime=0} ---
wait4(-1, [{WIFEXITED(s) && WEXITSTATUS(s) == 0}], WNOHANG, NULL) = 31628
wait4(-1, 0x7ffe73c0dc10, WNOHANG, NULL) = -1 ECHILD (No child...