IT16342: Channel processes terminate abnormally with probe ID XC130031 amqrmppa gets SIGSEGV in zsqATCBAfter

APAR status

• Closed as program error.

Error description

• An IBM MQ v8.0.0.5 queue manager with activity tracing enabled,
  channel processes abnormally terminated with SIGSEGV: address
  not mapped
  
  Error log shows
  AMQ7159: A FASTPATH application has ended unexpectedly.
  
  FDC generated with:
  
  Probe Id          :- XC130003
  Program Name      :- amqrmppa
  Thread            :- 211    AsyncConsume
  Probe Type        :- HALT6109
  Major Errorcode   :- STOP
  Comment1          :- SIGSEGV: address not mapped(0x8)
  
  MQM Function Stack
  zlaMainThread
  zlaProcessMessage
  zlaProcessMQIRequest
  zlaMQCB
  zsqMQCB
  zsqATCBAfter
  xcsFFST
  

Local fix

• Turn off activity tracing.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of activity tracing tracing and with fastpath channels
  enabled are at risk of being affected by this issue.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When an IBM MQ queue manager is configured to use fastpath
  channels (MQIBindType=FASTPATH in qm.ini) and activity trace is
  enabled, then changing a queue so that it becomes get inhibited
  can cause a SIGSEGV to occur and the channel process will end.
   The SIGSEGV is caused by IBM MQ referencing a piece of data
  which is not valid when the channel process is connected using
  fastpath MQI bindings.
  

Problem conclusion

• The code was modified to include a check that the data was valid
  before attempting to access it.
  
  It should be noted that when running with FASTPATH bindings then
  certain MQCBD fields may be missing from MQCB activity trace, as
  unused fields within the MQCBD will not be initialized in
  FASTPATH mode, and omitted from the output accordingly.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v7.5       7.5.0.8
  v8.0       8.0.0.6
  v9.0 CD    9.0.1
  v9.0 LTS   9.0.0.1
  
  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

  WMQ BASE MULTIP

• Fixed component ID

  5724H7251

Applicable component levels

• R800 PSY

     UP