PH59031: ABN=0C4-00000038,U=XXXXXXXX,C=MQ900.934.MMC -CSQMCLS2,M=CSQGFRCV,LOC=CSQTOPLM.CMQXKTPT+OFFSET

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Abend ABN=0C4-00000038,U=XXXXXXXX,C=MQ900.934.MMC
  -CSQMCLS2,M=CSQGFRCV,LOC=CSQTOPLM.CMQXKTPT+OFFSET happened and
  resulted in abnormal queue manager termination:
  
  QUEUE MANAGER ABNORMAL TERMINATION REASON=00F30420
  
  The 0C4 abend (and consequent qmgr termination, as the abend
  occurred on an SRB during deallocation processing) occurred due
  to a failure to access the subscription entry associated with a
  subscription handle.
  
  The storage was unavailable as it had been freed several days
  earlier, when the pubsub engine terminated - this was
  immediately after an ALT QMGR command, suggesting it was
  disabled at that point.
  
  During this processing CSQTOCTH is called for each subscription
  to check handles for references to the subscription being
  freed, and if found, invalidate them, however this clearly did
  not occur.
  
  Digging further, it was possible to see that there is an error
  that causes CSQTOTCH to abend, and silently retry, prior to the
  handles being checked - this results in handles being left with
  references to freed topic manager storage.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 3 Modification 0 and                 *
  *                 Release 4 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: During pubsub engine shutdown, it is    *
  *                      possible for an 0C4-00000038 abend to   *
  *                      occur.                                  *
  ****************************************************************
  The code which controls closing an open subscription handle
  during deallocation processing was incorrectly invalidating
  references to the 64bit publisher/subscriber control block. This
  caused the 0C4 abend to occur due to a search on an invalid
  64bit ACE address.
  

Problem conclusion

• The code has been changed to correctly invalidate all references
  to the 64bit publisher/subscriber control block during
  deallocation processing.
  

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:

  UI96840 UI98412

Modules/Macros

• CSQTOCTH
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R300 PSY UI96840

     UP24/06/27 P F406

• R400 PSY UI98412

     UP24/09/25 P F409  

Fix is available

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