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

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You can track all active APARs for this component.

 

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 number

    IZ01599

  • Reported component name

    WMQ LIN X86 V6

  • Reported component ID

    5724H7204

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2007-07-17

  • Closed date

    2007-07-25

  • Last modified date

    2007-07-30

  • 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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Document Information

Modified date:
30 July 2007