IV07652: JAVA JIT: CRASH IN JITWALKFRAME() DURING A GC CYCLE

APAR status

• Closed as program error.

Error description

• Error Message: SIGSEGV in JIT library running jitWalkFrame()
  .
  Stack Trace: {libj9jit24.so}{jitWalkFrame}
  {libj9jit24.so}{jitWalkStackFrames}
  {libj9vm24.so}{walkStackFrames}
  {libj9gc24.so}{scanSlots__28GC_VMThreadStackSlotIterator...}
  {libj9gc24.so}{scanOneThread__14MM_RootScanner...}
  {libj9gc24.so}{scanThreads__14MM_RootScanner...}
  {libj9gc24.so}{scanRoots__14MM_RootScanner...}
  {libj9gc24.so}{markRoots__16MM_MarkingScheme...}
  {libj9gc24.so}{markLiveObjects__16MM_MarkingScheme...}
  {libj9gc24.so}{run__19MM_ParallelMarkTask...}
  .
  

Local fix

• You can avoid the problem by using the following java command
  line parameter:
  -Xjit:disableNewInstanceImplOpt
  Note: Using this option will have a small effect on performance.
  The degree of the effect is based on how frequently the
  Class.newInstance() API is used by the java application.
  

Problem summary

• The JIT can compile helper routines to optimize calls to the
  Class.newInstance() API. If the JIT compiles a helper to
  optimize the case where Class.newInstance() is called against an
  array class and a GC is triggered when that helper is executing,
  the stack walker will crash with a SIGSEGV.
  

Problem conclusion

• This defect will be fixed in:
  5.0.0 SR13
  6.0.0 SR10
  6.0.1 SR1
  .
  The JIT was modified so that it will refuse to compile
  Class.newInstance() helpers against array classes
  .
  To obtain the fix:
  Install build 20110909 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:

  IV07653

Fix information

• Fixed component name

  JAVA 5 JIT

• Fixed component ID

  620500124

Applicable component levels

• R500 PSY

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