[jira] [Created] (ZOOKEEPER-2623) CheckVersion outside of Multi causes NullPointerException

["Diego Ongaro (JIRA)" <ji...@apache.org>]

Diego Ongaro created ZOOKEEPER-2623:
---------------------------------------

             Summary: CheckVersion outside of Multi causes NullPointerException
                 Key: ZOOKEEPER-2623
                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2623
             Project: ZooKeeper
          Issue Type: Bug
            Reporter: Diego Ongaro
            Priority: Minor


I wasn't sure if check version (opcode 13) was permitted outside of a multi op, so I tried it. My server crashed with a NullPointerException and became unusable until restarted. I guess it's not allowed, but perhaps the server should handle this more gracefully?

Here are the server logs:
{noformat}
Accepted socket connection from /0:0:0:0:0:0:0:1:51737
Session establishment request from client /0:0:0:0:0:0:0:1:51737 client's lastZxid is 0x0
Connection request from old client /0:0:0:0:0:0:0:1:51737; will be dropped if server is in r-o mode
Client attempting to establish new session at /0:0:0:0:0:0:0:1:51737
:Fsessionid:0x10025651faa0000 type:createSession cxid:0x0 zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a
Processing request:: sessionid:0x10025651faa0000 type:createSession cxid:0x0 zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a
Got zxid 0x60000065e expected 0x1
Creating new log file: log.60000065e
Committing request:: sessionid:0x10025651faa0000 type:createSession cxid:0x0 zxid:0x60000065e txntype:-10 reqpath:n/a
Processing request:: sessionid:0x10025651faa0000 type:createSession cxid:0x0 zxid:0x60000065e txntype:-10 reqpath:n/a
:Esessionid:0x10025651faa0000 type:createSession cxid:0x0 zxid:0x60000065e txntype:-10 reqpath:n/a
sessionid:0x10025651faa0000 type:createSession cxid:0x0 zxid:0x60000065e txntype:-10 reqpath:n/a
Add a buffer to outgoingBuffers, sk sun.nio.ch.SelectionKeyImpl@28e9f397 is valid: true
Established session 0x10025651faa0000 with negotiated timeout 20000 for client /0:0:0:0:0:0:0:1:51737
:Fsessionid:0x10025651faa0000 type:check cxid:0x1 zxid:0xfffffffffffffffe txntype:unknown reqpath:/
Processing request:: sessionid:0x10025651faa0000 type:check cxid:0x1 zxid:0xfffffffffffffffe txntype:unknown reqpath:/
Processing request:: sessionid:0x10025651faa0000 type:check cxid:0x1 zxid:0xfffffffffffffffe txntype:unknown reqpath:/
Exception causing close of session 0x10025651faa0000: Connection reset by peer
:Esessionid:0x10025651faa0000 type:check cxid:0x1 zxid:0xfffffffffffffffe txntype:unknown reqpath:/
IOException stack trace
java.io.IOException: Connection reset by peer
	at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
	at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39)
	at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
	at sun.nio.ch.IOUtil.read(IOUtil.java:197)
	at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
	at org.apache.zookeeper.server.NIOServerCnxn.doIO(NIOServerCnxn.java:320)
	at org.apache.zookeeper.server.NIOServerCnxnFactory$IOWorkRequest.doWork(NIOServerCnxnFactory.java:530)
	at org.apache.zookeeper.server.WorkerService$ScheduledWorkRequest.run(WorkerService.java:162)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Unexpected exception
java.lang.NullPointerException
	at org.apache.zookeeper.server.ZKDatabase.addCommittedProposal(ZKDatabase.java:252)
	at org.apache.zookeeper.server.FinalRequestProcessor.processRequest(FinalRequestProcessor.java:127)
	at org.apache.zookeeper.server.quorum.CommitProcessor$CommitWorkRequest.doWork(CommitProcessor.java:362)
	at org.apache.zookeeper.server.WorkerService$ScheduledWorkRequest.run(WorkerService.java:162)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Committing request:: sessionid:0x10025651faa0000 type:error cxid:0x1 zxid:0x60000065f txntype:-1 reqpath:n/a
Unregister MBean [org.apache.ZooKeeperService:name0=ReplicatedServer_id1,name1=replica.1,name2=Follower,name3=Connections,name4="0:0:0:0:0:0:0:1",name5=0x10025651faa0000]
Exception thrown by downstream processor, unable to continue.
CommitProcessor exited loop!
Closed socket connection for client /0:0:0:0:0:0:0:1:51737 which had sessionid 0x10025651faa0000
{noformat}

And here's a one-liner to repro, which does a ConnectRequest followed by a {{CheckVersion(path="/", version=89235}}}:
{noformat}
echo AAAALAAAAAAAAAAAAAAAAAAAJxAAAAAAAAAAAAAAABAAAAAAAAAAAAAAAAAAAAAAAAAAEQAAAAEAAAANAAAAAS8AAVyT | base64 --decode | nc localhost 2181 >/dev/null
{noformat}

This is against master as of a couple of weeks ago (f78061a). I haven't checked to see which versions are affected.



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