IV74913: JAVA JIT POWER: EXECUTING UNLOADED CODE

APAR status

• Closed as program error.

Error description

• Error Message: The error can show up in several ways but the
  most likely result of this problem is a SIGSEGV in JIT compiled
  code.
  .
  Stack Trace: N/A
  .
  The problem can only occur on Power hardware (AIX, LinuxPPC)
  

Local fix

• The problem will only occur in cases where "HCR" mode is used.
  That is when a Java agent is installed that requests the ability
  to replace classes. The problem can be avoided by removing the
  use of the Java agent. The problem can also be avoided by
  excluding the compilation of methods that are effected by the
  problem, but it might not be obvious which method(s) are/is
  causing the problem.
  -Xjit:exclude={<pkg/Class.method*>}
  

Problem summary

• The JIT needs to patch JIT compiled code that has inlined
  methods from a class that has been unloaded by the garbage
  collector when the classes classloader object has been freed. In
  rare cases the JIT might fail to register an assumption against
  the class to trigger the code patching when the class is
  unloaded.
  

Problem conclusion

• The JIT was modified so that assumptions are correctly
  registered.
  .
  This APAR will be fixed in the following Java Releases:
     6    SR16 FP15      (6.0.16.15)
     8    SR2             (8.0.2.0)
     7    SR9 FP20      (7.0.9.20)
     6 R1 SR8 FP15       (6.1.8.15)
     7 R1 SR3 FP20       (7.1.3.20)
  .
  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/
  
  Update: Fixed the Java Releases information.
  

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

• R600 PSY

     UP

• R130 PSY

     UP

• R260 PSY

     UP