Description:
------------
Following code crashing whole website.
A could reproduce it with php5.2.9-1 on Win7 (using WAMP).
I couldn't on 5.2.6 on FreeBSD configuration.


Reproduce code:
---------------
$data = "; \$Id: administerusersbyrole.info,v 1.1.2.1 2009/01/27 20:40:40 smokris Exp \$\nname = Administer Users by Role\ndescription = \"Allows users with 'administer users' permission and a role (specified in 'Permissions') to edit/delete other users with a specified role.  If the user being edited has multiple roles, the user doing the editing must have permission to edit ALL of the user being edited's roles.  Also provides control over user creation.  Works well in conjunction with <a href='http://drupal.org/project/role_delegation'>role_delegation</a>.\"\ncore = 6.x\n\n; Information added by drupal.org packaging script on 2009-01-28\nversion = \"6.x-1.3\"\ncore = \"6.x\"\nproject = \"administerusersbyrole\"\ndatestamp = \"1233114605\"\n\n";
preg_match_all('
    @^\s*                           # Start at the beginning of a line, ignoring leading whitespace
    ((?:
      [^=;\[\]]|                    # Key names cannot contain equal signs, semi-colons or square brackets,
      \[[^\[\]]*\]                  # unless they are balanced and not nested
    )+?)
    \s*=\s*                         # Key/value pairs are separated by equal signs (ignoring white-space)
    (?:
      ("(?:[^"]|(?<=\\\\)")*")|     # Double-quoted string, which may contain slash-escaped quotes/slashes
      (\'(?:[^\']|(?<=\\\\)\')*\')| # Single-quoted string, which may contain slash-escaped quotes/slashes
      ([^\r\n]*?)                   # Non-quoted string
    )\s*$                           # Stop at the next end of a line, ignoring trailing whitespace
    @msx', $data, $matches, PREG_SET_ORDER);


Expected result:
----------------
Continue execution.

Actual result:
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On Firefox: Connection Interrupted
On Chrome: Error 101 (net::ERR_CONNECTION_RESET): Unknown error.