Estoy usando FSOUserBundle y quiero anular loginAction, usé este método:

namespace PjDZ\UserBundle\Controller;
use FOS\UserBundle\Controller\SecurityController as BaseController;

class SecurityController extends BaseController {

public function loginAction(\Symfony\Component\HttpFoundation\Request $request)
{
    /** @var $session \Symfony\Component\HttpFoundation\Session\Session */
    $session = $request->getSession();

    // get the error if any (works with forward and redirect -- see below)
    if ($request->attributes->has(SecurityContext::AUTHENTICATION_ERROR)) {
        $error = $request->attributes->get(SecurityContext::AUTHENTICATION_ERROR);
    } elseif (null !== $session && $session->has(SecurityContext::AUTHENTICATION_ERROR))    {
        $error = $session->get(SecurityContext::AUTHENTICATION_ERROR);
        $session->remove(SecurityContext::AUTHENTICATION_ERROR);
    } else {
        $error = '';
    }

    if ($error) {
        // TODO: this is a potential security risk (see http://trac.symfony-project.org/ticket/9523)
        $error = $error->getMessage();
    }
    // last username entered by the user
    $lastUsername = (null === $session) ? '' : $session->get(SecurityContext::LAST_USERNAME);

    $csrfToken = $this->container->has('form.csrf_provider')
        ? $this->container->get('form.csrf_provider')->generateCsrfToken('authenticate')
        : null;


    return $this->renderLogin(array(
        'last_username' => $lastUsername,
        'error'         => $error,
        'csrf_token' => $csrfToken,
    ));
}
}

pero cuando intento mostrar / iniciar sesión, aparece una página en blanco, ¿alguna idea?. perdona mi mal ingles