IJ50877: JAVA JIT: INCORRECT ARGUMENT PASSED TO A JNI METHOD

APAR status

• Closed as program error.

Error description

• Error Message: The CICS Transaction Gateway logs show CTG8985E
  messages
  .
  Stack Trace: N/A
  .
  The issue was reported when using CICS Transaction Gateway on
  zOS and started appearing after upgrading to Java 8.0.8.5, but
  the issue is cross platform and it existed prior to 8.0.8.5. The
  issue could therefore appear on any J9 based JVM.
  

Local fix

• The problem can be avoided with a minor performance impact by
  using the following java command line option:
  -Xjit:disableDirectToJNI
  This option will prevent the JIT from generating a direct to JNI
  which inlines the JNI call-out setup in a non-JNI method. With
  this option in place, the JIT will still build a JNI thunk to
  optimize the JNI call-out sequence, but it will not do so from
  within non-JNI method compilations.
  

Problem summary

• The JIT was trying to make use of existing stack slots that had
  contained pointers to objects that are being now being passed as
  an argument to a JNI method, but in some rare cases the existing
  stack slot might have been reused to hold some other value
  resulting in an incorrect argument being passed to the JNI
  method.
  

Problem conclusion

• The JIT was modified so that reusing existing stack slots will
  only occur when we can know for sure that it still contains the
  object reference that we need for the JNI method argument.
  https://github.com/eclipse-openj9/openj9/pull/19321
  .
  This APAR will be fixed in the following Releases:
  .
  IBM Semeru Runtimes
     17              17.0.12.0
     11              11.0.24.0
  IBM SDK, Java Technology Edition
     8    SR8 FP26  (8.0.8.26)
  .
  Downloads and supplementary documentation can be found at the
  following locations:
  - For non z/OS operating systems:
    - IBM Semeru Runtimes, Version 11 and later
      https://www.ibm.com/semeru-runtimes/downloads/
    - IBM SDK, Java Technology Edition, Version 8
      https://www.ibm.com/support/pages/java-sdk-downloads/
  - For the z/OS operating system:
    - Java SDK Products on z/OS
      https://www.ibm.com/support/pages/java-sdk-products-zos
  

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