IZ01599: SIGSEGV IN KQIWAKEUPWAITER WHEN WAITER STATE RESET DURING STOP CHANNEL COMMAND

WebSphere MQ V6.0 for iSeries Fix Pack 6.0.2.3
WebSphere MQ V6.0 Fix Pack 6.0.2.3
WebSphere MQ 6.0 for HP OpenVMS Alpha and Itanium - Fix Pack 6.0.2.7
WebSphere MQ 6.0 for HP OpenVMS Alpha and Itanium - Fix Pack 6.0.2.10 (FP03)

APAR status

• Closed as program error.

Error description

• You get an FDC with probe XC130004 when you stop all of the
  active channels in order to perform a media backup of the qmgr.
  .
  The FDC's show the following pattern:
    XC130004  xehExceptionHandler  SIGSEGV: address not mapped
    ZL043050  zlaMainThread
    ZL043105  zlaMainThread
  
  The stack for the XC130004 will include the following functions:
  zsqSPICancelWaiter
  kpiCancelWaiter
  kqiWakeUpWaiter
  xcsFFST
  .
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  The kqiWakeUpWaiter function is called during a request to stop
  a channel abruptly, typically either as a result of a STOP CHL
  MODE(TERMINATE) | MODE(FORCE), or perhaps due to AdoptMCA
  processing.
  
  Platforms affected:
   All Distributed (iSeries, all Unix and Windows)
  ****************************************************************
  PROBLEM SUMMARY:
  The locking which stops a queue from changing state while a
  request to cancel a thread which is waiting for a message to
  arrive on that queue was incorrect, leaving a small window
  where a change in the queue state could result in the
  queue manager accessing uninitialized memory.
  

Problem conclusion

• Cancelling a waiting MQGET is not a performance sensitive
  operation, hence there is no need for fine grained locking in
  this function and the code has been changed to hold the queue
  lock for the duration of the search for the waiting MQGET.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
                     v6.0
  Platform           Fix Pack 6.0.2.3
  --------           --------------------
  Windows            U200279
  AIX                U811346
  HP-UX (PA-RISC)    U811630
  HP-UX (Itanium)    U811631
  Solaris (SPARC)    U811632
  Solaris (x86-64)   U811633
  iSeries            SI27288
  Linux (x86)        U811634
  Linux (x86-64)     U811635
  Linux (zSeries)    U811636
  Linux (Power)      U811637
  Linux (s390x)      U811638
  
  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 LIN X86 V6

• Fixed component ID

  5724H7204

Applicable component levels

• R600 PSY

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