PM89237: MQ 64 BIT JAVA APPLICATION FAILS WHEN CSQBLB16 DETECTS A 31 BIT STORAGE SHORTAGE. ABEND0C4 OCCURS WHEN MALLOC REQUEST FAILS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• MQ java 64 bit application has many threads waiting. The failing
  thread is trying to do an MQPUT of a 94MB message.
  An malloc request of 31 bit storage fails probably because there
  is insufficient contiguous storage available to provide a 94MB
  block.
  CSQBLB16 sets MQCC_FAILED and MQRC_ADAPTER_STORAGE_SHORTAGE but
  the logic is trying to access the 31 bit storage. This results
  in an 0c4.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 *
  *                 Release 0 Modification 1 and Release 1       *
  *                 Modification 0 using 64 bit WebSphere MQ     *
  *                 applications.                                *
  ****************************************************************
  * PROBLEM DESCRIPTION: When an application running in a 64-bit *
  *                      mode performs an API call to a local    *
  *                      queue manager, if storage below the bar *
  *                      is low, the application may abend 0C4.  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  An 0C4 can occur when a malloc for a buffer at the start of
  WebSphere MQ API function fails due to a lack of free storage.
  In this case, the malloc will set the buffer pointer to null. A
  post-allocation check detects this failure and sets MQCC_FAILED
  and MQRC_ADAPTER_STORAGE_SHORTAGE. However, following this,
  processing then continues. Instead of returning from the MQGET
  with the failure, and attempting to write to the location set in
  the pointer, the code tries to write to the buffer and this
  leads to an abend 0C4.
  
  The post-allocation check should return the above MQCC and MQRC
  response in this situation.
  
  The Information Center needs to be updated with regard to the
  above MQCC and MQRC response when making an MQ API call from
  an application running in 64-bit mode.
  

Problem conclusion

• The code has been changed to return from the API call if we
  are returned a null pointer by the malloc.
  
  Information Center topic fm13210_
  
  WebSphere MQ,
  Messages,
  API completion and reason codes,
  Reason codes,
  Reason code list,
  2127 (084F) (RC2127): MQRC_ADAPTER_STORAGE_SHORTAGE
  
  "On an MQCONN call, the adapter was unable to acquire storage."
  
  Should be amended to say,
  
  "During an MQCONN call (or any MQ API call when called from an
  application running in 64 bit mode), the adapter was unable to
  acquire storage."
  
  Also, the following paragraph should be added to the Programmer
  response.
  
  "For applications running in 64 bit mode, MQ API calls must
  allocate storage to copy the call parameters into the 31 bit
  region of the application address space.  Check that sufficient
  31 bit storage is available for the parameters of any current MQ
  API calls."
  010Y
  100Y
  CSQBLB16
  

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:

  UK94602 UK94603

Modules/Macros

• CSQBLB16
  

Fix information

• Fixed component name

  WMQ Z/OS V7

• Fixed component ID

  5655R3600

Applicable component levels

• R010 PSY UK94602

     UP13/07/24 P F307 Ž

• R100 PSY UK94603

     UP13/07/24 P F307 Ž

Fix is available

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