IV48538: CRASH IN A METHOD COMPILED AT HIGH OPT LEVEL

APAR status

• Closed as program error.

Error description

• Error Message: Under some circumstances the JIT compiler can
  incorrectly compile a method at high optimization level that
  includes profiling, resulting in the Java stack pointer being
  over-written with the C stack pointer.
  .
  Stack Trace: Because the problem causes corruption of the stack
  it is usually difficult to determine the call stack of the
  failing thread.
  .
  In the examples seen so far the failure occurs trying to execute
  non-executable code at the J9VMThread (failing rip == rbp).
  

Local fix

• The problem can be avoided by disabling the use of JIT
  profiling:
  -Xjit:disableProfiling
  This option will likely result in slightly less optimal code
  being generated for those methods that reach the very highest
  optimization levels and so may reduce the maximum performance of
  the application. The extent of any performance impact will
  depend on the details of each application.
  

Problem summary

• The problem is caused when a call to jitInstanceOf is placed
  within the control flow of a call to jitProfileValue, leading
  incorrect stack management.
  

Problem conclusion

• This defect will be fixed in:
  6.0.0 SR15
  6.0.1 SR7
  7.0.0 SR6
  .
  The JIT has been modified to handle this case correctly.
  

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