IV19615: INCORRECT CONDITIONAL ASSIGNMENT OF LONG CONSTANTS CAUSING ARRAY INDEXOUTOFBOUNDSEXCEPTION ON Z196

PM63541: SHIP SDK APARS IV18371+IV19615+IV20339 AS WSAS IFIX

APAR status

• Closed as program error.

Error description

• Error Message: An unexpected ArrayIndexOutOfBoundsException was
  observed with the following Java stack trace:
  java.lang.ArrayIndexOutOfBoundsException
  at
  org.apache.derby.impl.store.access.conglomerate.GenericScanContr
  oller.fetchRows(Unknown Source)
  at
  org.apache.derby.impl.store.access.heap.HeapScan.fetchNextGroup(
  Unknown Source)
  at
  org.apache.derby.impl.sql.execute.BulkTableScanResultSet.reloadA
  rray(Unknown Source)
  at
  org.apache.derby.impl.sql.execute.BulkTableScanResultSet.getNext
  RowCore(Unknown Source)
  at
  org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.getNe
  xtRowCore(Unknown Source)
  at
  org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.getNex
  tRow(Unknown Source)
  ...
  .
  Stack Trace: N/A
  .
  

Local fix

• This issue can be avoided using the -Xjit:disableZGryphon
  option. This option may cause a noticeable performance
  degradation.
  

Problem summary

• The problem occurs in the scenario where an if-statement is
  conditionally guarding a constant assignment to a long variable
  or field.
  i.e.:
   long x;
   if (....)
      x = -1;
  Depending on profiling information, the JIT compiler may
  incorrectly generate an unconditional store for the assignment,
  effectively ignoring the if-condition's value.  This may result
  in an incorrect value being set to the long variable / field.
  The problem will only occur on 64-bit JDKs on Linux on Z or zOS,
  running on z196 hardware.
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 SR2 FP1
  7.0.0 SR2
  .
  The JVM has been updated to generate the proper conditional
  store instruction.
  

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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