PH55894: MQ V9.3 STORAGE LEAK IN APPLICATION ADDRESS SPACES VIA ASYNC CONSUME MQ API

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• At MQ V9.3, there's a code defect that is passing a 31bit
  parameter into a procedure that treated the value as 64bits and
  a STORAGE RELEASE was issued for the incorrect length of zero
  causing a large amount of storage to be allocated below the bar
  in 31bit private storage.
  
  Keywords:  RFH eyecatcher in Subpool 0, Key 8 storage (SP0
  KEY8) Storage Build Up  IIB ABEND878
  
  The storage obtain is issued by CSQMALCH.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IBM MQ for z/OS Version 9       *
  *                 Release 3 Modification 0                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: Storage leak in MQ application          *
  *                      address space when using the Async      *
  *                      Consume MQ API over local bindings.     *
  ****************************************************************
  When using the Async Consume MQ API and connected to MQ via
  local bindings, storage for message buffers in the application
  address space is managed by MQ code.
  
  When a larger buffer is required, the previous buffer should
  be freed and released back to z/OS for reuse. However, in some
  circumstances this is not occurring, and over time the extended
  private storage in the application address space may be
  exhausted, leading to an S878 abend.
  

Problem conclusion

• Processing has been amended to ensure that the old buffer is
  correctly freed when allocating a new internal buffer for a
  larger message.
  

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:

  UI93014

Modules/Macros

• CSQMALCH
  

Fix information

• Fixed component name

  IBM MQ Z/OS V9

• Fixed component ID

  5655MQ900

Applicable component levels

• R300 PSY UI93014

     UP23/08/19 P F308 ¢

Fix is available

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