PH52094: ABN=0C4-00000011,LOC=CSQMLPLM.CSQMCALH+0000053A

APAR status

• Closed as duplicate of another APAR.

Error description

• The STOP MODE(FORCE) service task was doing deallocation
  processing for a task from job SMDSSCM. It was in the process
  of closing all the handles for open queues for the task and
  abended 0C4-11 reading data from an AMS QInfo control block,
  which is in the application address space. The abend occurs
  because the storage has been freed because the TCB which
  allocated the task-owned storage had ended.
  
  This is similar scenario to the problem in APAR PH37729. During
  the development of that fix, we incorrectly determined that the
  problem only applied to CICS connections.
  
  In summary, the problem is a timing window during deallocation
  processing which can occur when applications are doing work
  with AMS protected queues and a STOP QMGR MODE(FORCE) command
  is issued.
  .
  Additional Symptoms:
  0D5-00000021,LOC=CSQMLPLM.CSQMCALH+0000050E
  ABEND0D5 ABENDS0D5 S00D5
  

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

• Users Affected:
  All users of IBM MQ for z/OS Version 9
  Release 3 Continuous Delivery (CD) Release.
  
  Problem Description:
  Abend 0C4 occurs when STOP MODE(FORCE) is issued, while an
  active task has open handles to AMS protected queues.
  
  Problem Summary:
  During STOP MODE(FORCE) processing, allied tasks are notified
  that the queue manager is ending, and agents are driven through
  alternate agent termination.
  If an allied task had handles to AMS protected queues, these
  are closed during agent termination, and the associated QInfo
  control block is freed. However if the owning task had already
  ended this control block is already free, leading to abend 0C4
  when attempting to reference and free it again.
  
  Problem Conclusion:
  Storage management of AMS control blocks in the allied address
  space is enhanced to prevent alternate agent termination freeing
  blocks multiple times.
  
  The fix is targeted for delivery in APAR PH60453.
  

APAR Information

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

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

Fix information

Applicable component levels