Current code logic not check the pointer before use it. This may has potential issue, this patch add code to check it. Cc: Ruiyu Ni <ruiyu.ni@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Eric Dong <eric.dong@intel.com> Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com> Reviewed-by: Hao Wu <hao.a.wu@intel.com>