[...]
07:50:48.362655 poll([{fd=3, events=POLLIN}, {fd=7, events=POLLIN}], 2, -1) = 1 ([{fd=7, revents=POLLIN|POLLHUP}])
07:50:48.367202 recvfrom(7, "", 8, MSG_WAITALL, NULL, NULL) = 0
07:50:48.367287 poll([{fd=3, events=POLLIN}], 1, -1) = ? ERESTART_RESTARTBLOCK (Interrupted by signal)
07:51:12.493581 --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=29817, si_uid=0, si_status=0, si_utime=896, si_stime=124} ---
07:51:12.493646 write(4, "21", 1)      = 1
07:51:12.493717 rt_sigreturn({mask=[]}) = -1 EINTR (Interrupted system call)
07:51:12.493769 poll([{fd=3, events=POLLIN}], 1, -1) = 1 ([{fd=3, revents=POLLIN}])
07:51:12.493820 read(3, "21", 1)       = 1
[...]