IT44710: IBM MQ FDC with probe ID XC006001 is generated by the 'amqrmppa'process during 'endmqm' call

APAR status

• Closed as program error.

Error description

• The MQ Administrator uses the 'endmqm' program to end a queue
  manager.  This results in an FDC being generated by the
  'amqrmppa' process, containing the following data:
  
    Probe Id          :- XC006001
    Component         :- xcsFreeMemFn
    Program Name      :- amqrmppa
    Major Errorcode   :- xecS_I_PRIVATE_MEMORY_ERROR
    Probe Description :- AMQ6091I: An internal IBM MQ error has
  occurred.
    Comment1          :- invalid head tag
  

Local fix

• Make sure any channel exit modules used by MQ channels do not
  fail with memory faults, such as SIGSEGV or SIGBUS on UNIX and
  Linux systems.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All users of IBM MQ running custom channel exit programs.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When an IBM MQ channel pooling process ('amqrmppa') ends, either
  because the queue manager was requested to stop or because the
  process was idle, and a channel exit causes a memory exception,
  there is a small chance that the 'amqrmppa' process will write
  an FFST with Probe Id 'XC006001', from the component:
  
    xcsFreeMemFn
  
  as a result of trying to free the same memory twice.  Apart from
  the FFST, this error does not impact other queue manager
  functionality as the 'amqrmppa' process was on the verge of
  ending any way.
  

Problem conclusion

• The code has been updated such that the potential double-free of
  allocated memory is avoided, ensuring that the FFST from
  'xcsFreeMemFn' no longer occurs even if there is an exception
  within a channel exit module when a channel pooling process
  exits.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v9.2 LTS   9.2.0.30
  v9.3 LTS   9.3.0.25
  v9.4 LTS   9.4.0.5
  v9.x CD    9.4.1
  
  The latest available maintenance can be obtained from
  'IBM MQ Recommended Fixes'
  https://www.ibm.com/support/pages/recommended-fixes-ibm-mq
  
  If the maintenance level is not yet available information on
  its planned availability can be found in 'IBM MQ
  Planned Maintenance Release Dates'
  https://ibm.biz/mqplannedmaintenance
  
  ---------------------------------------------------------------
  

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

  MQ BASE V9.2

• Fixed component ID

  5724H7281

Applicable component levels