PI77034: WMQ 900: AN ABEND0C4 OCCURS IN CSQSCON2 WHEN MQ IS ATTEMPTING TOCONTRACT A PHB CONTAINING KEY8 SHB BLOCKS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• ABN=0C4-00000004 may occur in CSQSCON2+00000D56 when the queue
  manager is attempting to contract a PHB containing key8 SHB
  control blocks.
  Additional Symptom(s) Search Keyword(s):
  ABEND0C4 ABENDS0C4 S0C4 S00C4 0C4 CSQSLD1
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users of IBM MQ for z/OS Version 9 Release 0             *
  * Modification 0.                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Abend 0C4 occurs in CSQSCON2 when storage contraction occurs *
  * due to a short on storage (SOS) condition, and using Cluster *
  * Workload Exits.                                              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * None                                                         *
  ****************************************************************
  During storage contraction processing, CSQSCON2 attempted to
  free unused storage from MQ storage pools. After locating an
  empty SHB that had previously been used by a cluster workload
  exit, it tried to remove the empty SHB from the PHB chain.
  The SHB was in a different storage key, and so CSQSCON2 switched
  key before updating the previous SHB in the chain and set
  SHBNEXT to the new next element in the chain. However obtaining
  the new value required referencing working storage, which was
  fetch protected, causing the operation to abend 0C4.
  

Problem conclusion

• CSQSCON2 is changed to correctly update the chain of SHBs during
  storage contraction, when the SHBs are allocated using a
  different storage key.
  

Temporary fix

Comments

APAR Information

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

  PI76549

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

  UI45210

Modules/Macros

• CSQSCON2
  

Fix information

• Fixed component name

  MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R000 PSY UI45210

     UP17/03/30 P F703

Fix is available

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