PH23564: IBM MQ ABENDS4E3 ABN= 0C4-00000004 C=MQ900.910.CHIN,M=CSQXDISP

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• MQ Development finds that the XGWA does not contain a valid
  pointer to PFPROCESS. In analysis, the main PubSub Daemon task
  had failed. This was caused by queue SYSTEM.HIERARCHY.STATE
  being unavailable. Due to a timing window one of the additional
  PubSub threads started up and attempted to reference the
  pFProcess field, however that had now been freed and cleared
  (rendering it invalid). An ABEND0C4 resulted from there. MQ
  Development will investigate an improvement to serialization
  between the PubSub threads at startup.
  

Local fix

• Define the queue SYSTEM.HIERARCHY.STATE
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 1 Modification 0 and Release 2       *
  *                 Modification 0.                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: If an error condition is detected       *
  *                      during startup of the queued Pub/Sub    *
  *                      Daemon, a timing window exists whereby  *
  *                      a Pub/Sub subtask may start before the  *
  *                      Daemon terminates. This may result in   *
  *                      S0C4 abends in the CHIN for the Pub/Sub *
  *                      Daemon and for the Pub/Sub subtask.     *
  ****************************************************************
  During startup of the Pub/Sub Daemon, fields are set in the
  xGwa.PSDaemon MQ control block to track its progress. Inadequate
  checking of these fields results in it being possible for a
  Pub/Sub subtask to start before the Pub/Sub Daemon has finished
  its startup processing.
  
  These fields will be cleared during shutdown of the Pub/Sub
  daemon. The subtasks reference these fields unconditionally and
  without adequate serialisation, which may lead to them
  terminating with an ABEND0C4.
  

Problem conclusion

• The serialisation has been improved to remove these timing
  windows during termination of the Pub/Sub daemon.
  

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:

  UI75425 UI75426

Modules/Macros

• CSQXFCTL
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R100 PSY UI75426

     UP21/05/29 P F105

• R200 PSY UI75425

     UP21/05/29 P F105

Fix is available

• Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.