Fix for NULL buffer past to gwbuf_length

server/core/buffer.c

@@ -284,7 +284,11 @@ unsigned int
 gwbuf_length(GWBUF *head)
 {
 int	rval = 0;
-        CHK_GWBUF(head);
+
+	if (head)
+	{
+	        CHK_GWBUF(head);
+	}
 	while (head)
 	{
 		rval += GWBUF_LENGTH(head);