目前，我正在尝试查找并修复错误，但无法找到。
我在登录表单上输入我的帐户和密码。
当我输入正确的用户名时，无论我输入错误的密码还是正确的密码，都可以登录

public function dangnhap(){
        $this->load->library('form_validation');
        $this->form_validation->set_rules('username', 'Tài khoản', 'required|min_length[6]|max_length[32]');
        $this->form_validation->set_rules('password', 'Mật khẩu', 'required|min_length[6]|max_length[32]');
        if($this->form_validation->run() ==TRUE){
            $username = $_POST['username'];
            $password = md5($_POST['password']);
            if($this->Mcustomer->customer_login($username, $password)!=FALSE){
                $row = $this->Mcustomer->customer_login($username, $password);
                $this->session->set_userdata('sessionKhachHang',$row);
                $this->session->set_userdata('id',$row['id']);
                $this->session->set_userdata('email',$row['email']);
                $this->session->set_userdata('sessionKhachHang_name',$row['fullname']);
                if($this->session->userdata('cart')){
                    redirect('gio-hang','refresh');
                }else{
                    redirect('thong-tin-khach-hang','refresh');
                }
            }else{
                $this->data['error']='Tài khoản hoặc mật khẩu không chính xác';
                $this->data['title']='Đăng nhập tài khoản';
                $this->data['view']='dangnhap';
                $this->load->view('frontend/layout',$this->data);
            }
        }else{
            $this->data['title']='Smart store - Đăng nhập tài khoản';
            $this->data['view']='dangnhap';
            $this->load->view('frontend/layout',$this->data);
        }     
    }

有没有人有办法？请帮帮我。谢谢大家