Description:
------------
See reproducible code below


Reproduce code:
---------------
<?

/**
    cross-referencing memory leak.
    PHP garbage collector doesn't free memory for 
    cross-referencing objects. It could be great
    problem for daemons or services, written on PHP
*/
function memleak($size)
{
    $a = str_repeat('a', $size);
    // construct child
    $child = array(
        'data' => $a,
    );
    // construct parent
    $parent = array(
        'data' => $a,
        'child' => &$child,
    );
    // comment following line to prevent memleak
    $child['parent'] = &$parent;
}

// try to leak of 1GB memory
for ($i = 0; $i < 1000; $i++) memleak(1000000);

sleep(10);

?>

Expected result:
----------------
normal execution of script

Actual result:
--------------
PHP occupies all available memory.