script process in timeout

Question

I'm running a PHP script... and with an indefinite range the script stops working but the process continues running

poll([{fd=5, events=POLLIN|POLLERR|POLLHUP}], 1, 3000) = 0 (Timeout)
poll([{fd=5, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN|POLLERR|POLLHUP}], 1, 3000) = 0 (Timeout)
poll([{fd=5, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN|POLLERR|POLLHUP}], 1, 3000) = 0 (Timeout)
poll([{fd=5, events=POLLIN|POLLPRI|POLLERR|POLLHUP}], 1, 0) = 0 (Timeout)
poll([{fd=5, events=POLLIN|POLLERR|POLLHUP}], 1, 3000) = 0 (Timeout)

What is this?

and how can prevent it?