IJ38084: CRASH WHILE GENERATING JAVACORE, OR JAVACORE CONTAINS 'UNABLE TO WALK IN-FLIGHT DATA ON CALL STACK' INSTEAD OF JAVA STACK.

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEGV/GPF is received when a user attempts to
  generate javacore with "kill -3".
  OR
  In the javacore generated by "kill -3" using default dump agent,
   many threads show "Unable to walk in-flight data on call stack"
   message instead of java stack within "Thread Details" section.
  .
  Stack Trace:
  For the crash issue:
    #0  walkLiveMonitorSlots
    #1  jitGetOwnedObjectMonitors
    #2  getOwnedObjectMonitorsIterator
    #3  walkFrame
    #4  jitWalkStackFrames
    #5  walkStackFrames
    #6  getOwnedObjectMonitors
    #7  JavaCoreDumpWriter::getOwnedObjectMonitors
    #8  protectedGetOwnedObjectMonitors
    #9  omrsig_protect
    #10 JavaCoreDumpWriter::writeThread
    #11 JavaCoreDumpWriter::writeThreadsWithNativeStacks
  .
  

Local fix

• For "Unable to walk in-flight data on call stack"
  -----------------------------------------------------
  Use the following JVM options:
  -Xdump:java:none:events=user
  -Xdump:java:events=user,request=exclusive+prepwalk+preempt
  
  The first option disables the default javacore generation on
  user signal, and the second one enables it with different
  request flags.
  
  Note that even the workaround may sometimes fail to produce the
  java stack.
  

Problem summary

• There are cases where a non-JVM thread may trigger a javacore.
  This will result in crash when JVM needs to walk certain JIT
  frames.
  

Problem conclusion

• The JVM has been updated to prevent the crash from occurring
  when non-JVM thread triggers the javacore.
  This also fixes the issue with displaying the java stack within
  the javacore.
  .
  This APAR will be fixed in the following Java Releases:
  .
  IBM Semeru Runtime Certified Edition
    11              11.0.15.0
  IBM SDK, Java Technology Edition
    8    SR7 FP6    (8.0.7.6)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

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

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels