It's not a Bug, but crash PHP. Maybe it's proposital way to prevent a type of DoS.

Sometimes it's usefull or it's need use a function that call itself. An example is a recursive array routine.

<?PHP
function crash($foo) {
    crash($foo);
}
crash("foo");
?>

What I like to show is: windows crash PHP when this code run. This is expected or the right is show a Fatal Error mensage?