IT21548: Client connection fails and a FDC is cut with probe XR014005 reporting a null pointer exception

APAR status

• Closed as program error.

Error description

• The NPE causes the channel to fail.  It takes manual
  intervention to get it going again.
  .
  The logs report:
  7/18/17 14:23:52.467  AMQXR0022I: Client 'client name'
  previously connected at network address 'ipaddress' now
  connected at
  'ipaddress'.
  7/18/17 14:23:53.276  AMQUT1003I: 30 instances of message
  'AMQXR0022I:'
  were suppressed.
  7/18/17 14:23:53.275  AMQCO2001E: An error (probe: XR014005)
  occurred
  and a Failure Data Capture (FDC) file has been written to file
  '/var/mqm/errors/MQXR0.FDC'.
  7/18/17 14:23:54.308  AMQCO1006I: Channel 'channelname' has
  stopped
  7/18/17 15:51:50.408  AMQXR0016I: Channel 'channelname' has
  started
  .
  The FDC reports a NPE.
  .
  java.lang.NullPointerException
      at
  com.ibm.mq.MQXRService.MQTTServerSession.purge
    (MQTTServerSession.java:462)
      at
  com.ibm.mq.MQXRService.MQTTServerContext.close
    (MQTTServerContext.java:225)
      at
  com.ibm.mq.communications.NonBlockingConnection.closeFinal
    (NonBlockingConnection.java:667)
      at
  com.ibm.mq.communications.NonBlockingConnection.sendRemainder
    (NonBlockingConnection.java:338)
      at
  com.ibm.mq.communications.NonBlockingWorker.run
    (NonBlockingWorker.java:402)
      at java.lang.Thread.run(Thread.java:809)
  

Local fix

• NA
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  The issue affects the users of:
  
   - IBM MQ Telemetry (MQXR) service V8
   - IBM MQ Telemetry (MQXR) service V9
  
   who have a client connecting to the MQXR service.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  There was a small timing window where if a MQTT client request
  is being made to close the client connection that got just got
  closed by another thread on the MQXR service, a close request
  was made on the closed connection object, which resulted in a
  NullPointerException. This exception caused the MQXR channel to
  stop and cut probe XR014005.
  

Problem conclusion

• The timing window where the NullPointerException could occur has
  been removed, and the exception no longer occurs.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.9
  v9.0 CD    9.0.5
  v9.0 LTS   9.0.0.3
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WMQ BASE MULTIP

• Fixed component ID

  5724H7251

Applicable component levels

• R800 PSY

     UP