PH57881: ABN=5C6-00D40068 ABEND

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• The 5C6-00D40068 abend is occurring in CSQM1PAW due to a
  pointer to an MHND control block, which represents a handle to
  an open queue, which is zero. CSQM1PAW is being called as part
  of agent deallocation from CSQMDALL.
  
  The MHND address is being obtained from an MPDO control block
  associated with a queue. The problem is that this queue is
  being deleted at the same time as CSQMDALL is running, most
  likely because the queue is a temporary dynamic queue.
  Though module CSQMDALL does check for this scenario, the
  serialisation is not watertight, which can result in the MPDO
  being freed from underneath the CSQMDALL SRB, resulting in the
  5C6-00D40068 abend.
  
  The problem is a small timing window between a queue being
  deleted and an application ending.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version         *
  *                 9 Release 3 Modification 0.                  *
  ****************************************************************
  * PROBLEM DESCRIPTION: An 5C6-00D40068 abend is seen in the    *
  *                      Queue Manager Address Space.            *
  ****************************************************************
  A timing window exists between a queue being deleted and an
  application that was using the queue ending resulting in an
  5C6-00D40068 abend.
  

Problem conclusion

• The code has been updated to remove the timing window.
  

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:

  UI95791

Modules/Macros

• CSQM1PAW
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R300 PSY UI95791

     UP24/03/19 P F403

Fix is available

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