IC92207: MODULE AMQMTMGC MAKES A CALL COGETOBJECTCONTEXT WITHOUT HAVING MADE A PREVIOUS COINITIALIZEEX CALL.

WebSphere MQ V7.0 Fix Pack 7.0.1.11
Fix Pack 7.1.0.4 for WebSphere MQ V7.1
WebSphere MQ V7.5 Fix Pack 7.5.0.3

APAR status

• Closed as program error.

Error description

• The amqmtmgc module makes a call to the Microsoft Windows COM
  method CoGetObjectContext() without first making a call to
  CoInitializeEx(). Whilst this is not usually a problem, if
  another thread successfully initializes the COM before the
  amqmtmgc calls CoGetObjectContext(), a timing window in the
  COM code can result in a memory access violation.
  
  The call stack at crash time is:
  
  ole32!OXIDEntry::InitRundown
  ole32!CComApartment::InitRemoting
  ole32!CComApartment::StartServer
  ole32!InitChannelIfNecessary
  ole32!CoGetObjectContext
  amqmtmgc!<Unknown Function>
  QFA_2_1_2!QFA::MqChannel::getImqChannel
  QFA_2_1_2!QFA::MqQueueManager::open
  QFA_2_1_2!Qfa2UfoMqDevice::initialize
  QFA_2_1_2!Qfa2UfoMqDevice::onStart
  QFA_2_1_2!Qfa2UfoMqDevice::startThread
  MSVCR100D!_callthreadstartex
  MSVCR100D!_threadstartex
  kernel32!BaseThreadInitThunk
  ntdll!__RtlUserThreadStart
  ntdll!_RtlUserThreadStart
  

Local fix

• A possible workaround could be to call CoInitializeEx on their
  thread before calling MQCONNX. This should prevent the access
  violation.
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  All users of WebSphere MQ 7.0, 7.1, and 7.5.
  
  Platforms affected:
  Windows
  
  ****************************************************************
  PROBLEM SUMMARY:
  The access violation reported occurred because the MQ code made
  a call to CoGetObjectContext() without first making a call to
  the COM library CoIntializeEx() method, which the Microsoft COM
  documentation states is a requirement. Without calling
  CoInitalizeEx() a race condition can occur with another thread
  which may result in an access violation ending the process.
  

Problem conclusion

• The code has been altered to ensure that CoInitializeEx() is
  always called before an attempt is made to call
  CoGetObjectContext(), thereby avoiding the race condition which
  can cause an access violation.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following:
  
                     v7.0
  Platform           Fix Pack 7.0.1.11
  --------           --------------------
  Windows            7.0.1.11
  
                     v7.1
  Platform           Fix Pack 7.1.0.4
  --------           --------------------
  Windows            7.1.0.4
  
  Version            v7.5
  --------           --------------------
  Fix available in:  7.5.0.3
  
  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 WINDOWS V7

• Fixed component ID

  5724H7220

Applicable component levels

• R701 PSY

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