IJ12158: INCORRECT METHOD EXECUTION AFTER HCR METHOD REDEFINITION

APAR status

• Closed as program error.

Error description

• Error Message: When using a JVMTI or Java agent to redefine Java
  method bytecode during execution, the user may be able to
  observe that a previous version of a method is executed under
  rare circumstances. These circumstances will involve methods
  compiled after JITSTARTUP using nextGenHCR. The JIT may fail to
  place an OSR guard after some loop asyncchecks.
  .
  Stack Trace: N/A
  .
  The problem is limited to Java 8sr5 up to and including fp26
  (8.0.5.0 through 8.0.5.26)
  

Local fix

• The problem can be circumvented with -Xjit:disableNextGenHCR.
  

Problem summary

• The JIT dataflow analysis used to implement method redefinition
  support for nextGenHCR may fail to place transitions at all
  points required to prevent execution continuing in JITed code
  after a method redefinition.
  

Problem conclusion

• The dataflow analysis has been enhanced to ensure appropriate
  transitions are placed at all required points to prevent
  entering the wrong version of a method after redefinition.
  .
  This APAR will be fixed in the following Java Releases:
   8 SR5 FP27 (8.0.5.27)
  .
  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:

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels