[HBASE-22050] NPE happens while RS shutdown, due to atomic violation

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.0.0-alpha-1
• Component/s: regionserver
• Assignee: lujie
• Reporter: lujie
• Created: 13/Mar/19 13:03
• Updated: 13/Mar/19 16:39

Description

while RS shutdown, the RS#abort are called due to

handler.AssignRegionHandler: Fatal error occured while opening region hbase:meta,,1.1588230740, aborting...

And in abort:

2428.if (rssStub != null && this.serverName != null) {
2429   ReportRSFatalErrorRequest.Builder builder =
2430.  ReportRSFatalErrorRequest.newBuilder();
2431.  builder.setServer(ProtobufUtil.toServerName(this.serverName));
2432   builder.setErrorMessage(msg);
2433   rssStub.reportRSFatalError(null, builder.build());
2434 }

2428-2434 are assumed to be atomic, but if it step in the 2429-2433, meanwhile RS#run:

1149 // Make sure the proxy is down.
1150 if (this.rssStub != null) {
1151    this.rssStub = null;
1152 }

So the rssStub == null and NPE happens

2019-03-14 04:49:53,016 WARN [RS_CLOSE_META-regionserver/hadoop12:16020-0] regionserver.HRegionServer: Unable to report fatal error to master
java.lang.NullPointerException
at org.apache.hadoop.hbase.regionserver.HRegionServer.abort(HRegionServer.java:2433)
at org.apache.hadoop.hbase.regionserver.handler.AssignRegionHandler.handleException(AssignRegionHandler.java:154)
at org.apache.hadoop.hbase.executor.EventHandler.run(EventHandler.java:106)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

I think we should avoid the NPE.