IZ74899: JAVA JIT PPC - CRASH WITH A MEMORY/REGISTER INCONSISTENCY

APAR status

• Closed as program error.

Error description

• Error Message: A SIGSEV encountered in jitInstanceOf.
  .
  Stack Trace: N/A
  .
  The contents of memory as seen in the core file is inconstant
  with the register values loaded from memory moments before the
  crash occurred.
  

Local fix

• The problem can be avoid by using the following Java command
  line parameter:
  -Xjit:disableEscapeAnalysis
  Using this option will prevent the JIT from using an
  optimization that can cause this problem, but it will also cause
  the JIT to generate less optimal code and will have a slight
  impact on the performance of the application.
  

Problem summary

• The JIT incorrectly removes memory synchronization instructions
  that must be executed before exposing newly created objects to
  other threads when running on multi-CPU PowerPC machines. The
  problem only exists in rare cases where a catch block follows a
  normal code block and both blocks create new objects.
  

Problem conclusion

• This defect will be fixed in:
  6.0.0 SR9
  5.0.0 SR12
  .
  The JIT was modified so that it will no longer incorrectly
  remove memory synchronization instructions.
  .
  To obtain the fix:
  Install build 20100511 or later
  

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:

  IZ74900

Fix information

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R600 PSN

     UP