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PM17126: DURING CONTROL REGION STARTUP A POSSIBLE LOOP OR HANG CAN OCCUR.

Fixes are available

7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for AIX
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for HP-UX
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for IBM i
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Linux
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Solaris
7.0.0.13: WebSphere Application Server V7.0 Fix Pack 13 for Windows
7.0.0.13: Java SDK 1.6 SR8FP1 Cumulative Fix for WebSphere Application Server
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for AIX
7.0.0.15: Java SDK 1.6 SR9 Cumulative Fix for WebSphere Application Server
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for HP-UX
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for IBM i
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Linux
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Solaris
7.0.0.15: WebSphere Application Server V7.0 Fix Pack 15 for Windows
7.0.0.17: WebSphere Application Server V7.0 Fix Pack 17
7.0.0.17: Java SDK 1.6 SR9 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.19: WebSphere Application Server V7.0 Fix Pack 19
7.0.0.21: WebSphere Application Server V7.0 Fix Pack 21
7.0.0.23: WebSphere Application Server V7.0 Fix Pack 23
7.0.0.25: WebSphere Application Server V7.0 Fix Pack 25
7.0.0.27: WebSphere Application Server V7.0 Fix Pack 27
7.0.0.29: WebSphere Application Server V7.0 Fix Pack 29
7.0.0.31: WebSphere Application Server V7.0 Fix Pack 31
7.0.0.27: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.33: WebSphere Application Server V7.0 Fix Pack 33
7.0.0.35: WebSphere Application Server V7.0 Fix Pack 35
7.0.0.37: WebSphere Application Server V7.0 Fix Pack 37
7.0.0.39: WebSphere Application Server V7.0 Fix Pack 39
7.0.0.41: WebSphere Application Server V7.0 Fix Pack 41
7.0.0.43: WebSphere Application Server V7.0 Fix Pack 43
7.0.0.45: WebSphere Application Server V7.0 Fix Pack 45
7.0.0.19: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.21: Java SDK 1.6 SR9 FP2 Cumulative Fix for WebSphere
7.0.0.23: Java SDK 1.6 SR10 FP1 Cumulative Fix for WebSphere
7.0.0.25: Java SDK 1.6 SR11 Cumulative Fix for WebSphere Application Server
7.0.0.27: Java SDK 1.6 SR12 Cumulative Fix for WebSphere Application Server
7.0.0.29: Java SDK 1.6 SR13 FP2 Cumulative Fix for WebSphere Application Server
7.0.0.45: Java SDK 1.6 SR16 FP60 Cumulative Fix for WebSphere Application Server
7.0.0.31: Java SDK 1.6 SR15 Cumulative Fix for WebSphere Application Server
7.0.0.35: Java SDK 1.6 SR16 FP1 Cumulative Fix for WebSphere Application Server
7.0.0.37: Java SDK 1.6 SR16 FP3 Cumulative Fix for WebSphere Application Server
7.0.0.39: Java SDK 1.6 SR16 FP7 Cumulative Fix for WebSphere Application Server
7.0.0.41: Java SDK 1.6 SR16 FP20 Cumulative Fix for WebSphere Application Server
7.0.0.43: Java SDK 1.6 SR16 FP41 Cumulative Fix for WebSphere Application Server
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APAR status

  • Closed as program error.

Error description

  • During Control Region startup a possible loop or hang can occur
    in HashMap.findNonNullKeyEntry, from
    com/ibm/ws/xcf/groupservices/NameConverterZos.short2longName
    .
    The symptom will be a showing of HashMap.findNonNullKeyEntry and
    com/ibm/ws/xcf/groupservices/NameConverterZos.short2longName
    from thread dumps.
    .
    In summary, the stack from the dump will look like this:
    java/util/HashMap.findNonNullKeyEntry
    java/util/HashMap.getEntry
    java/util/HashMap.get
    com/ibm/ws/xcf/groupservices/NameConverterZos.short2longName
    com/ibm/ws/xcf/groupservices/GenLivenessPluginZoS.notifyMemberIn
    fo
    com/ibm/ws/xcf/groupservices/GenLivenessServiceXCF.notifyMemberI
    nfo
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  All users of IBM WebSphere Application Server
    *                  V7.0                                        *
    ****************************************************************
    * PROBLEM DESCRIPTION: During Control Region startup a loop    *
    *                      or hang can occur in Hashmaps used by   *
    *                      the NameCoverterZos class.              *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    During the Control Region startup, a loop or hang may occur. A
    Java stacktrace from the dump of the Control Region may show
    one or more threads executing HashMap methods called from the
    NameConverterZos class similar to the following:
    
    java/util/HashMap.findNonNullKeyEntry
    java/util/HashMap.getEntry
    java/util/HashMap.get
    com/ibm/ws/xcf/groupservices/NameConverterZos.short2longName
    com/ibm/ws/xcf/groupservices/GenLivenessPluginZoS.notifyMemberIn
    fo
    com/ibm/ws/xcf/groupservices/GenLivenessServiceXCF.notifyMemberI
    nfo
    
    The problem occurs because the use of HashMaps in the
    NameConverterZos class is not properly synchronized. During
    periods of heavy use, such as server startup, concurrent
    attempts to update a HashMap can cause a number of exceptions
    or other error conditions.
    

Problem conclusion

  • The NameConverterZos class has been changed so that methods
    that read or update the HashMaps are synchronized to insure
    that multiple threads do not access HashMaps concurrently.
    
    Consideration should also be given to applying SDK APAR
    IZ73767, which fixes a related, but wider, problem with
    HashMap multi-threading.
    
    APAR PM17126 is currently targeted for inclusion in
    Service Level (7.0.0.13) of WebSphere Application Server
    
    Please refer to URL:
    //www.ibm.com/support/docview.wss?rs=404&uid=swg27006970
    for Fix Pack availability.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM17126

  • Reported component name

    WEBSPHERE FOR Z

  • Reported component ID

    5655I3500

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-06-23

  • Closed date

    2010-08-24

  • Last modified date

    2010-11-02

  • 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

    WEBSPHERE FOR Z

  • Fixed component ID

    5655I3500

Applicable component levels

  • R700 PSY UK61146

       UP10/10/21 P F010

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.



Document information

More support for: WebSphere Application Server for z/OS
General

Software version: 7.0

Reference #: PM17126

Modified date: 02 November 2010