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PM81813: PLUG-IN DEADLOCK BETWEEN TRYING TO READ/LOAD A NEW PLUGIN CONFIGURATION AND STARTING AN ESI MONITOR THREAD TO A SERVER

A fix is available

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APAR status

  • Closed as program error.

Error description

  • The plugin is in a mutex deadlock: one thread owns the
    configuration mutex and is waiting on the the esi mutex, and
    there is another thread that owns the esi mutex and is wating on
    the configuration mutex. All incoming requests will try to get
    the configuration mutex, so they will all get hung up.
    

Local fix

  • Turning the esi invalidator off bypasses the problem.
    <Property Name="ESIInvalidationMonitor" Value="false"/>
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:  IBM WebSphere Application Server web        *
    *                  server plugin V6.1.0 users                  *
    ****************************************************************
    * PROBLEM DESCRIPTION: Deadlock can occur when reloading       *
    *                      configuration and processing requests   *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    If there are frequent configuration changes such that the
    plugin configuration is being reload and requests are being
    processed, a deadlock situation can occur where the processing
    request and the reload are both waiting for a semaphore. This
    will only occur if ESI caching is enabled.
    

Problem conclusion

  • Change has been made to avoid the deadlock situation. If you
    are disabling ESI caching, it is recommended to stop and
    restart the webserver instead of a dynamic reload.
    
    APAR PM81813 is currently targeted for inclusion in Fix Pack
    6.1.0.47 of WebSphere Application Server V6.1.
    
    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

    PM81813

  • Reported component name

    WEBSPHERE FOR Z

  • Reported component ID

    5655I3500

  • Reported release

    610

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2013-01-31

  • Closed date

    2013-03-21

  • Last modified date

    2013-10-04

  • APAR is sysrouted FROM one or more of the following:

    PM75801

  • 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

  • R610 PSY UK97031

       UP13/09/07 P F309

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: 6.1

Reference #: PM81813

Modified date: 04 October 2013