IV86435: JIT INCORRECTLY OPTIMIZES LOCKS CAUSING GC ASSERT

APAR status

• Closed as program error.

Error description

• Error Message: The snap trace describes a failed assertion:
  
  ** ASSERTION FAILED ** at ParallelScavenger.cpp:2993:
  ((MM_StackSlotValidator(MM_StackSlotValidator::NOT_ON_HEAP,
  *slotPtr, stackLocation, walkState).validate(_env)))
  .
  Stack Trace: java/nio/HeapByteBuffer.<init>(II)V
  java/nio/ByteBuffer.allocate(I)Ljava/nio/ByteBuffer;
  org/apache/cassandra/utils/memory/SlabAllocator.getRegion()Lorg/
  apache/cassandra/utils/memory/SlabAllocator$Region;
  org/apache/cassandra/utils/memory/SlabAllocator.allocate(ILorg/a
  pache/cassandra/utils/concurrent/OpOrder$Group;)Ljava/nio/ByteBu
  ffer;
  Customer may experience other similar call stack.
  .
  

Local fix

• dontInline={org/apache/cassandra/utils/concurrent/Locks.monitorE
  nterUnsafe*,org/apache/cassandra/utils/concurrent/Locks.monitorE
  xitUnsafe*}
  

Problem summary

• This is a problem with JIT live monitor metadata. The
  optimization incorrectly made some assumption which is untrue in
  this corner case. The problem could appear on x, power, or z.
  

Problem conclusion

• JIT has been updated to handle this special case.
  .
  This APAR will be fixed in the following Java Releases:
   7 R1 SR3 FP50 (7.1.3.50)
   6 R1 SR8 FP30 (6.1.8.30)
   8 SR3 FP10 (8.0.3.10)
   7 SR9 FP50 (7.0.9.50)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
   https://www.ibm.com/developerworks/java/jdk/
  

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:

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R130 PSY

     UP

• R260 PSY

     UP