PH62307: USE J9 JAVADUMP API FOR THREAD DUMPS WHEN AVAILABLE

APAR status

• Closed as program error.

Error description

• Internal thread dumps are created by sending a SIGQUIT signal to
  the process, the handling of which can be changed by system dump
  handlers.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: Thread dumps produced internally by the *
  *                      WebSphere server can be triggered using *
  *                      SIGQUIT signals                         *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  WebSphere Application Server allows components to trigger thread
  dumps using an internal API, which does so by sending a SIGQUIT
  signal to the process (the equivalent of a "kill -3" command on
  Unix platforms). This can be problematic for users who have
  configured their server's dump handlers to perform other tasks,
  such as production of heap dumps, on the SIGQUIT signal, or who
  have suppressed dump generation.
  The J9 JVM provides a convenience "JavaDump" method
  (https://eclipse.dev/openj9/docs/api/jdk8/platform/jvm/com/ibm/j
  vm/Dump.html#JavaDump--) that can be used to produce javacore
  files (the J9 version of a thread dump) without triggering the
  dump handler, making it a safer and more reliable means of
  producing these dumps.
  

Problem conclusion

• The internal thread dump API was updated to utilize the J9
  JavaDump method when available. Solaris and HP-UX platforms
  (which are out of standard support) will retain the legacy dump
  behavior.
  
  The fix for this APAR is targeted for inclusion in fix packs
  8.5.5.27 and 9.0.5.22. For more information, see 'Recommended
  Updates for WebSphere Application Server':
  https://www.ibm.com/support/pages/node/715553
  

Temporary fix

Comments

APAR Information

• 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

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels