IJ11621: X86 CRASH WITH GC ASSERTION RUNNING JIT COMPILED METHOD

APAR status

• Closed as program error.

Error description

• Error Message: The assertion will look similar to:
  j9mm.479    *   ** ASSERTION FAILED ** at
  ../../gc_glue_java/MarkingSchemeRootMarker.cpp:48:
  ((MM_StackSlotValidator(0, object, stackLocation,
  walkState).validate(_env)))
  .
  Stack Trace: N/A
  .
  The bad data will be in a register or stack slot associated with
  an inline arraycopy sequence.
  

Local fix

• There is no single option to disable the generation of these
  optimized arraycopies. Not inlining and excluding affected
  methods may reduce the frequency of assertions but may have a
  noticeable adverse affect on performance.
  

Problem summary

• When generating an optimized inline arraycopy sequence, the JIT
  could fail to mark a register containing a pointer to somewhere
  inside the array as an internal pointer. This would mean the GC
  would look to update the pointer when moving objects leading to
  the assertion being triggered.
  

Problem conclusion

• This JIT compiler implementation was updated to correctly mark
  all pointers to the inside of an array generated as part of an
  inline arraycopy sequence as internal pointers.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP26  (8.0.5.26)
  .
  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:

Fix information

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels