Fixes#726.
This prevents a segmentation fault by checking the pointer
before accessing it.
Change-Id: I18a3776fbcd6242c6efd1b88044debaa88c7342f
Signed-off-by: Claire J. In <claire.in@circuitblvd.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/449591
Reviewed-by: wuzhouhui <wuzhouhui@kingsoft.com>
Reviewed-by: Konrad Sztyber <konrad.sztyber@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Darek Stojaczyk <dariusz.stojaczyk@intel.com>
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>