PM95003: WMQ ABEND0C4 CSQL1RCL +0000090C

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Level 3 sees that there is a window in which 64-bit storage
  contraction (as a result of the CSQY224E) can occur while a
  thread is in the process of obtaining a 64-bit quickcell
  element from the free-chain. The storage contraction
  (CSQSQC64) can then result in the freeing of the storage
  extent containing the allocated quickcell element, which
  results in the 0C4 seen here (this would occur if the
  storage contraction takes place after the CSQSGC64 macro
  has checked  CSQS_QP64_UNIQ_RES1 but before the CSQSGC64
  macro has set QCEL_64.csId.
  Additional Symptom(s) Search Keyword(s):
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
  *                 Release 1 Modification 0.                    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Erroneous free of 64bit quick cell pool *
  *                      storage when queue manager is           *
  *                      undergoing cell pool contraction may    *
  *                      result in S0C4 abends occurring.        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When a queue manager is short on 64bit storage above the bar and
  issues message CSQY224I indicating that it is attempting to free
  all unused storage above the bar, it is possible that a timing
  condition occurs where a cell from a pool is allocated
  immediately before the pool contraction occurs, but it not
  marked as in use immediately. This in-use cell may be
  incorrectly classified as being free and the queue manager may
  subsequently free the extent even though there are elements in
  use.
  
  Once the storage has been freed, any procedure attempting to use
  the cell pool storage may abend with an S0C4.
  

Problem conclusion

• Processing has been amended to allow for cell allocations from
  the pool, prior to initiating the contraction process.
  
  In addition, a logic error where subsequent contractions may
  fail to correctly occur has also been corrected.
  100Y
  CSQSQC64
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UI13094

Modules/Macros

• CSQSQC64
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R100 PSY UI13094

     UP13/12/24 P F312 Ž

Fix is available

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