title: The page isn't redirecting properly when i try to call drupal_get_form
body: <p>Why Drupal 7 cannot redirect properly (I've logged in)?</p>
  
  <p>When I'm trying to call drupal_get_form('user_login') from my module in hook_preprocess_page(), the browser throw that message.</p>
  
  <p>Thank you!</p>