IV09461: CRASH IN GC DUE TO BAD STACKSLOTS

APAR status

• Closed as program error.

Error description

• Error Message: The problem could occur on system Z only:
  <OSB>java<CSB> 0000000A5A30D700: Invalid class pointer in stack
  allocated object in thread main \
  <OSB>java<CSB> 0000000A5A30D700:   O-Slot=0000000BA0FF9580 \
  <OSB>java<CSB> 0000000A5A30D700:   O-Slot value=0000000BA0FF71B8
  \
  <OSB>java<CSB> 0000000A5A30D700:   PC=000000001ED0874E \
  <OSB>java<CSB> 0000000A5A30D700:   framesWalked=21 \
  <OSB>java<CSB> 0000000A5A30D700:   arg0EA=0000000BA0FF9618 \
  <OSB>java<CSB> 0000000A5A30D700:   walkSP=0000000BA0FF70A0 \
  <OSB>java<CSB> 0000000A5A30D700:   literals=0000000B3CED7268 \
  <OSB>java<CSB> 0000000A5A30D700:   jitInfo=0000000B9ADB7B58 \
  <OSB>java<CSB> 0000000A5A30D700:   method=0000000B3C8D7C78 \
  (com/ibm/icm/da/portable/schema/BuildCompType.buildCompType1(Lco
  m/ibm/icm/da/IBuildCompTypeInput;)Lcom/ibm/icm/da/IBuildCompType
  Output;) (JIT) \
  <OSB>java<CSB> 0000000A5A30D700:
  stack=0000000BA0FF0750-0000000BA0FF9F70 \
  <OSB>java<CSB> 18:19:22.681 0xa5ba1eb00    j9mm.479    *   **
  ASSERTION FAILED ** at ./ParallelScavenger.cpp:2381: \
  ((MM_StackSlotValidator(MM_StackSlotValidator::NOT_ON_HEAP,
  *slotPtr, stackLocation, walkState).validate(_env))) \
  <OSB>java<CSB> JVMDUMP006I Processing dump event 'traceassert',
  detail '' - please wait. \avenger.cpp:2381: \
  .
  Stack Trace: N/A
  .
  

Local fix

• Excluding this method from being compiled by the JIT:
  for the above example:
  -Xjit:exclude={com/ibm/icm/da/portable/schema/BuildCompType.buil
  dCompType1(Lcom/ibm/icm/da/IBuildCompTypeInput;)Lcom/ibm/icm/da/
  IBuildCompTypeOutput;}
  However this might introduce performance degradation as the
  method will be interpreted.
  

Problem summary

• The problem is caused by a bad stack slot mapping for long
  displacements
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 SR1
  .
  The JVM has been updated to correctly map the long displacement
  slots
  .
  To obtain the fix:
  Install build 20110602 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:

Fix information

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels

• R260 PSY

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