Index: wp-login.php
===================================================================
--- wp-login.php	(revision 15646)
+++ wp-login.php	(working copy)
@@ -531,7 +531,11 @@
 	if ( !$secure_cookie && is_ssl() && force_ssl_login() && !force_ssl_admin() && ( 0 !== strpos($redirect_to, 'https') ) && ( 0 === strpos($redirect_to, 'http') ) )
 		$secure_cookie = false;
 
-	$user = wp_signon('', $secure_cookie);
+	if ( is_user_logged_in() ) {
+		$user = wp_get_current_user();
+	} else {
+		$user = wp_signon('', $secure_cookie);
+	}
 
 	$redirect_to = apply_filters('login_redirect', $redirect_to, isset( $_REQUEST['redirect_to'] ) ? $_REQUEST['redirect_to'] : '', $user);