IV44465: CRASH IN JIT LIBRARY DURING LIVE MONITOR ANALYSIS

APAR status

• Closed as program error.

Error description

• Error Message: none
  .
  Stack Trace: TR_SetMonitorStateOnBlockEntry::set
  TR_CodeGenerator::doInstructionSelection
  TR_CodeGenerator::generateCodePhase1
  TR_CodeGenerator::generateCode
  .
  

Local fix

• The problem method can be excluded from JIT compilation by using
  an option of the form:
  
  -Xjit:exclude={package/classname.methodname(*}
  

Problem summary

• The JIT compiler assumed that, for a given path of a program,
  the monitor enters and monitor exits must be balanced (i.e. the
  number of enters must be equal to the number of exits, and
  enters and exits are processed in the correct order). However,
  some Java bytecode obfuscators can produce bytecodes that are
  functionally correct but violate this assumption.
  

Problem conclusion

• This defect will be fixed in:
  6.0.0 SR15
  6.0.1 SR7
  7.0.0 SR6
  .
  The JIT compiler has been modified so that it will abort
  compilations where unbalanced monitors are detected.
  

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

• R600 PSY

     UP

• R260 PSY

     UP