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IY93752: EXCESSIVE DNS LOOKUPS

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • MQ/GSKit is causing a loop when a socket closes unexpectedly.
    Trace shows that the GSKit ccigsk_secure_sock_read calls a tcp
    routine (cciTcpSslReadCallback).  This is expecting a return
    code and errno but MQ is only setting the return code.  This
    causes it to retry after waiting 250 ms.  Each time this happens
    , we make a DNS lookup call.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users exploiting SSL and suffering from unexpected client
    termination. It is very difficult to predict under what
    circumstances the code might be unlucky enough to return
    an errno to GSKit which might imply a retry is appropriate.
    
    Platforms affected:
     All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    The interface between MQ and GSKit involves registering a
    callback function for reading data from TCP. This interface
    specification states that when a negative return code is set
    then an appropriate errno should be set, however MQ is not
    setting the errno appropriately.
    

Problem conclusion

  • Set errno to an appropriate value in the MQ SSL read callback
    function.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v5.3
    Platform           Fix Pack 14
    --------           --------------------
    Windows            U200266
    AIX                U808477
    HP-UX (PA-RISC)    U808478
    Solaris (SPARC)    U808480
    iSeries            SI24366
    Linux (x86)        U808481
    Linux (zSeries)    U808483
    
                       v6.0
    Platform           Fix Pack 6.0.2.2
    --------           --------------------
    Windows            U200270
    AIX                U809895
    HP-UX (PA-RISC)    U809898
    HP-UX (Itanium)    U810084
    Solaris (SPARC)    U809913
    Solaris (x86-64)   U810362
    iSeries            SI27286
    Linux (x86)        U809950
    Linux (x86-64)     U810178
    Linux (zSeries)    U810081
    Linux (Power)      U810083
    Linux (s390x)      U810110
    
    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

    IY93752

  • 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

    2007-01-18

  • Closed date

    2007-02-28

  • Last modified date

    2007-07-27

  • 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

       UP

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Document Information

Modified date:
27 July 2007