nil pointer check
nil pointer check

f0/cadvisor,shilpamayanna/cadvisor,ncdc/cadvisor,BrickXu/cadvisor,timstclair/cadvisor,dchen1107/cadvisor,jhjeong-kr/cadvisor,erSitzt/cadvisor,linux-on-ibm-z/cadvisor,erSitzt/cadvisor,ncdc/cadvisor,f0/cadvisor,dchen1107/cadvisor,f0/cadvisor,IFTTT/cadvisor,linux-on-ibm-z/cadvisor,BrickXu/cadvisor,shilpamayanna/cadvisor,ainsleyc/cadvisor,erSitzt/cadvisor,derekwaynecarr/cadvisor,ncdc/cadvisor,derekwaynecarr/cadvisor,guoshimin/cadvisor,IFTTT/cadvisor,ncdc/cadvisor,jhjeong-kr/cadvisor,derekwaynecarr/cadvisor,dchen1107/cadvisor,timstclair/cadvisor,ncdc/cadvisor,timstclair/cadvisor,ainsleyc/cadvisor,jhjeong-kr/cadvisor,linux-on-ibm-z/cadvisor,dchen1107/cadvisor,derekwaynecarr/cadvisor,ainsleyc/cadvisor,BrickXu/cadvisor,IFTTT/cadvisor,datawisesystems/cadvisor,jhjeong-kr/cadvisor,f0/cadvisor,erSitzt/cadvisor,IFTTT/cadvisor,ainsleyc/cadvisor,erSitzt/cadvisor,IFTTT/cadvisor,derekwaynecarr/cadvisor,guoshimin/cadvisor,f0/cadvisor,jhjeong-kr/cadvisor,BrickXu/cadvisor,BrickXu/cadvisor,dchen1107/cadvisor,guoshimin/cadvisor,datawisesystems/cadvisor