IV47046: THROWING A JAVA EXCEPTION CAUSES A CRASH IN LIBJ9VM26.SO ON POWE R

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEGV or GPF is raised in libj9vm26.so on
  POWER platforms (Linux or AIX), when a Java program tries to
  throw an exception.
  .
  Stack Trace:
  java/lang/J9VMInternals.getStackTrace(Native Method)
  java/lang/Throwable.getInternalStackTrace(Throwable.java:208(Com
  piled Code))
  java/lang/Throwable.printStackTrace(Throwable.java:399(Compiled
  Code))
  java/lang/Throwable.printStackTrace(Throwable.java:245(Compiled
  Code))
  ...
  
  Native stack trace:
  #12 getOriginalROMMethod
  #13 iterateStackTrace
  #14 getStackTrace
  #15 java_lang_J9VMInternals_getStackTrace
  .
  

Local fix

• This problem can be avoided with the JVM option -Xnoclassgc but
  this might result in a memory leak if dynamic class loading is
  in use.
  
  The problem can also be avoided by preventing the JIT compiler
  from inlining methods that could be unloaded without the root
  method also being unloaded at the same time. The following
  option is expected to do so for less than 20% loss in
  performance:
  
  -Xjit:disableVirtualInlining
  
  A more conservative workaround would be to disable inlining
  entirely:
  
  -Xjit:disableInlining
  

Problem summary

• The problem is caused by the JIT compiler incorrectly handling
  unloaded methods on POWER platforms.
  

Problem conclusion

• This defect will be fixed in:
  7.0.0 SR6
  6.0.1 SR7
  6.0.0 SR15
  .
  The JIT compiler has been updated to prevent the crash from
  occurring when a stack walk involves unloaded methods.
  

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

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R260 PSY

     UP

• R600 PSY

     UP