IT42851: Memory leak in the IBM MQ amqzlaa0 process

APAR status

• Closed as program error.

Error description

• The IBM MQ amqzlaa0 process uses an increasing amount of system
  memory.
  

Local fix

• This issue may occur when an application which connects to an
  IBM MQ agent (amqzlaa0) process ends unexpectedly.  If it is
  possible to avoid this happening then the memory leak will not
  occur.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue occurs when a locally connected application ends
  unexpectedly when calling MQGET with a large message buffer.
  The connected application might be a user application or an IBM
  MQ process, such as amqrmppa.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  If an application that is connected to an IBM MQ agent process
  (amqzlaa0) ended unexpectedly while calling MQGET, then there
  was a window where a memory buffer used to store the message was
  not correctly freed.  This resulted in a memory leak in the
  amqzlaa0 process.
  
  The affected code is triggered only if very large message
  buffers were used - those exceeding approximately 8MB.
  

Problem conclusion

• The code has been corrected to free the allocated memory if the
  connected application ends while the MQGET call is in progress.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.1 LTS   9.1.0.20
  v9.2 LTS   9.2.0.20
  v9.3 LTS   9.3.0.10
  v9.x CD    9.3.4
  
  The latest available maintenance can be obtained from
  'WebSphere MQ Recommended Fixes'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'WebSphere MQ
  Planned Maintenance Release Dates'
  http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
  ---------------------------------------------------------------
  

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:

Fix information

• Fixed component name

  IBM MQ BASE MP

• Fixed component ID

  5724H7271

Applicable component levels