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IZ42988: SIGSEGV IN PTHREAD_KILL CALLED FROM XCSREQUESTMUTEXSEMFULL

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APAR status

  • Closed as program error.

Error description

  • SIGSEGV in pthread_kill called from xcsRequestMutexSemFull
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This problem could hypothetically affect any user on Linux
    using the MQCNO_HANDLE_SHARE_BLOCK or
    MQCNO_HANDLE_SHARE_NOBLOCK. Note that the MQJMS java/JMS
    bindings use these options, even if the customers applications
    do not use the options directly.
    
    Platforms affected:
    Linux (Power),Linux (s390x),Linux (x86),Linux (x86-64),
    Linux (zSeries)
    
    ****************************************************************
    PROBLEM SUMMARY:
    After the queue manager has been waiting for a while for a lock
    then if the current lock owner is in the same process as the
    waiter the pthread_kill function is used to send signal 0
    to the owning thread. The return value from this function
    allows the lock waiter to check that the owner is still alive
    and to inherit the lock if that is not the case.
    Due to a timing/locking condition related to
    MQCNO_HANDLE_SHARE_BLOCK/MQCNO_HANDLE_SHARE_NO_BLOCK where the
    lock ownership ended while the waiter was taking this action
    then an invalid pthread_t value was passed to the pthread_kill
    function which then caused the SIGSEGV.
    

Problem conclusion

  • A check was added to cater for the possibility of the pthread_t
    becoming invalid when the health check on the lock owner
    is performed.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v6.0
    Platform           Fix Pack 6.0.2.7
    --------           --------------------
    Linux (x86)        U822325
    Linux (x86-64)     U822358
    Linux (zSeries)    U822329
    Linux (Power)      U822327
    Linux (s390x)      U822357
    
    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

    IZ42988

  • 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

    2009-02-02

  • Closed date

    2009-02-10

  • Last modified date

    2009-02-10

  • 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:
10 February 2009