IJ01916: CRASH IN GC ON STACK ALLOCATED OBJECT

APAR status

• Closed as program error.

Error description

• Error Message: Version 8.0.5.0 (Java 8 SR5) crashes during GC
  when running with -XX:-EnableHCR (i.e. with HCR disabled). This
  is a non-default setting and is unlikely to be encountered in
  normal use.
  .
  Stack Trace: While the exact location of the crash will vary,
  the stack will include stackAllocatedObjectSlotWalkFunction,
  e.g.
  0x00007fdc311e85c8
  {libj9gc29.so}{_ZN12MM_Scavenger14rememberObjectEP22MM_Environme
  ntStandardP8J9Object} <OSB>0x7fdbdfddc3f8<CSB>
  0x00007fdc311e8752
  {libj9gc29.so}{_ZN12MM_Scavenger16rescanThreadSlotEP22MM_Environ
  mentStandardPP8J9Object} <OSB>0x7fdbdfddc400<CSB>
  0x00007fdc31c818ff
  {libj9jit29.so}{stackAllocatedObjectSlotWalkFunction}
  <OSB>0x7fdbdfddc460<CSB>
  0x00007fdc31080bdb {libj9gc29.so}{j9mm_iterate_object_slots}
  <OSB>0x7fdbdfddc470<CSB>
  0x00007fdc31c81b71 {libj9jit29.so}{walkJITFrameSlots}
  <OSB>0x7fdbdfddc5b0<CSB>
  0x00007fdc31c8212a {libj9jit29.so}{jitWalkFrame}
  <OSB>0x7fdbdfddc630<CSB>
  .
  

Local fix

• HCR is enabled by default, so the crash can only happen if the
  the -XX:-EnableHCR and the related -Xjit:disableNextGenHCR are
  used. Removing these options and restarting the JVM will avoid
  the problem.
  If running with HCR is not possible for some reason, the use of
  -Xjit:disableEscapeAnalysis should also prevent the crash,
  however this will likely impose some degree of performance
  overhead. The extent of any such overhead will vary from
  application to application.
  

Problem summary

• Under rare circumstances the JIT failed to correctly initialise
  an object reference before the GC accessed it. Stale data in the
  object reference could then cause the GC to crash.
  

Problem conclusion

• The JIT has been modified to ensure that object references in
  stack allocated objects are correctly initialized before they
  can be inspected by the GC.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP5   (8.0.5.5)
  .
  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

• R130 PSY

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