Description:
------------
I'm referring to the "bug" descriped here : http://bugs.php.net/bug.php?id=10675&edit=1 . I would recommend that you add a warning on the "Program Execution Functions" documentation page which basically advises the programmer to close any open session before calling exec() or other related functions as otherwise the PHP script may hang!

Reproduce code:
---------------
session_start();
exec('ls');

// Save this, open the page in a browser and reload repeatedly. After several successful reloads, the page will just hang

Expected result:
----------------
nothing, the correct code seems to be:

session_start();
/*
.... code ...
*/
session_write_close();
exec('ls');
@session_start();

// There's no locking in this code