Facebook login showing not defined index: email only for gmail users - facebook

Question

I've made App and facebook login for my site. But I've tested it and it works for another type of mail. I tried now with gmail and it's showing:
ErrorException [ Notice ]: Undefined index: email
My method for that is:
public function action_fbLogin(){
$facebook = new Facebook(array(
'appId' => 'MyAppId',
'secret' => 'MySecret',
));
$user = $facebook->getUser();
if ($user) {
$user_profile = $facebook->api('/me', array('fields' => 'id,email,name,first_name,last_name,picture'));
$user_id = Model_UserFunctions::checkIfUserExist($user_profile['email']);
if($user_id > 0)
{
Session::instance()->set('user', array(
'fb_id' => $user_profile['id'],
'user_id' => $user_id,
'pic' => $user_profile['picture'],
'email' => $user_profile['email'],
'first_name' => $user_profile['first_name'],
'last_name' => $user_profile['last_name'],
));
$this->redirect('profile');
exit;
}
$values = array(
'email' => $user_profile['email'],
'username' => $user_profile['email'],
'password' => '12345678'
);
$user = ORM::factory ( 'User' );
$user->values($values);
try
{
if($user->save()){
$user_new_id = $user->as_array();
$user_new_id = $user_new_id['id'];
Session::instance()->set('user', array(
'fb_id' => $user_profile['id'],
'user_id' => $user_new_id,
'pic' => $user_profile['picture'],
'email' => $user_profile['email'],
'first_name' => $user_profile['first_name'],
'last_name' => $user_profile['last_name'],
));
$this->redirect('profile');
}
}
catch (ORM_Validation_Exception $e)
{
$result = $e->errors('models');
echo '<pre>';
print_r($result);
exit;
}
}
else
{
$this->redirect($facebook->getLoginUrl(array('id,email,name,first_name,last_name,picture')));
}
exit;
}
Are there other things that I should add to my code for gmail users? Thank you in advance!
Edited: my method for logut is:
public function action_logout(){
Session::instance()->delete('user');
$this->redirect('/');
}
Maybe problem is that it doesn't logout. I'm not sure. It shows me the same user data although I'm logged with different user.