PM42424: DEADLOCKED THREADS WITH SESSION TRACING ACTIVE

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• With session tracing active, customers may experience a deadlock
  in threads attempting to write out trace entries.  The
  deadlocked threads will be:
  .
  java/lang/String.valueOf
  java/lang/StringBuffer.append
  com/ibm/ws/session/utils/LRUHashMap$CacheEntryWrapper.toString
  java/text/MessageFormat.subformat
  java/text/MessageFormat.format
  ..
  and:
  .
  com/ibm/ws/session/store/common/BackedHashMap.superRemove
  com/ibm/ws/session/store/mtm/MTMHashMap.superRemove
  com/ibm/ws/session/store/mtm/MTMHashMap.removePersistedSession
  com/ibm/ws/session/store/common/BackedStore.removeSession
  ...
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of IBM WebSphere Application Server    *
  *                 V6.1 who have enabled session trace          *
  *                 may experience a rare deadlock.              *
  *                                                              *
  ****************************************************************
  * PROBLEM DESCRIPTION: A deadlock may occur with session       *
  *                      tracing enabled.                        *
  *                                                              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  When session tracing is enabled, extra session information
  is logged under synchronization. Under some rare timing
  sequence when multiple threads are accessing a given session
  simultaneously, a deadlock might result.
  

Problem conclusion

• Code changes have been made to the trace messages to avoid the
  synchronization points that could deadlock.
  
  APAR PM42424 is currently targeted for inclusion in Service
  Level (Fix Pack) 6.1.0.39 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:

  PM16861

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

Modules/Macros

• BBGUBINF BBOUBINF
  

Fix information

• Fixed component name

  WEBSPHERE FOR Z

• Fixed component ID

  5655I3500

Applicable component levels

• R610 PSY UK69361

     UP11/07/16 P F107

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.