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IV47968: MQ APPLICATION LIBRARIES HANG IN FORKED CHILD PROCESS WHEN EXEC OF AMQZXMSG0 FAILS

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APAR status

  • Closed as program error.

Error description

  • WebSphere MQ uses a program called 'amqxmsg0' to write to the
    Websphere MQ error log when the MQ error logging function
    encounters error when writing to the MQ error log. 'amqxmsg0'
    is spawned using fork and exec system calls by MQ
    libraries from within WebSphere MQ Applications. In some
    circumstances, the spawning of amqzxmsg0 might hang with the
    following stack trace.
    
    Forked child process:
    
    ....
    xeeCallWriteMsgProgram () from /opt/mqm/lib64/libmqe_r.so
    xcsDisplayMessage () from /opt/mqm/lib64/libmqe_r.so
    xcsDisplayMessageForSubpoolError () from .../lib64/libmqe_r.so
    rrxReportError () from /opt/mqm/lib64/libmqe_r.so
    ....
    main ()
    
    Application(Parent process)
    
    waitpid () from /lib64/libpthread.so.0
    xeeCallWriteMsgProgram () from /opt/mqm/lib64/libmqe_r.so
    xcsDisplayMessage () from /opt/mqm/lib64/libmqe_r.so
    xcsDisplayMessageForSubpoolError () from .../lib64/libmqe_r.so
    rrxReportError () from /opt/mqm/lib64/libmqe_r.so
    ....
    main ()
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users running MQ applications having complex C++ class
    destructors and atexit handlers
    
    Platforms affected:
    All Unix
    
    ****************************************************************
    PROBLEM SUMMARY:
    This problem occurred because WebSphere MQ used the exit system
    call instead
    of the _exit function when spawning the amqxmsg0 process.
    

Problem conclusion

  • WebSphere MQ has been modified to use the _exit function instead
    of the exit
    system call when spawning the amqxmsg0 process.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v7.0       7.0.1.12
    v7.1       7.1.0.5
    v7.5       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 number

    IV47968

  • Reported component name

    WMQ AIX V7

  • Reported component ID

    5724H7221

  • Reported release

    701

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-09-06

  • Closed date

    2013-10-18

  • Last modified date

    2013-10-18

  • 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 AIX V7

  • Fixed component ID

    5724H7221

Applicable component levels

  • R701 PSY

       UP

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Document Information

Modified date:
18 October 2013