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

Obtain the fix for this APAR.

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 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.