IZ50173: PROGRAM CHECK IN JITED CODE AFTER CLASS UNLOADED AND THEN RELOAD ED

APAR status

• Closed as program error.

Error description

• Problem Description:
  
  Delgating Reflection functions are incorrectly inlined by the
  JIT. The optimized code does not correctly check for unloaded
  classes. This can cause failures while executing code that has
  been JITed.
  
  The stack trace may contain reflection methods similar to any
  of the following:
   - sun/reflect/GeneratedConstructorAccessor##
   - sun/reflect/GeneratedMethodAccessor##
   - sun/reflect/DelegatingConstructorAccessorImpl.newInstance
   - sun/reflect/DelegatingMethodAccessorImpl.invoke
  near or at the top of the Java stack.
  
  JVM trace may show the class encountering a problem having been
  recently unloaded.
  
  This only applicable to z/OS or z/Linux.
  
  Keywords:
  
  ABENDS0C4 JIT Crash RUNCALLINMETHOD ABENDS0C1 ABEND0C4 ABEND0C1
  

Local fix

• Resolved in Java 5 SR10
  

Problem summary

• when a method A.method is compiled which inlined B.invoke. Class
  A is from bootstrapClassloader and never be unloaded. Class B
  from delegating classloader and it was unloaded. We tested class
  B before executing B.invoke. So after class B being unloaded, we
  have no chance to execute inlined B.invoke. However, we saw from
  the dump that 2 seconds before the crash, class C was loaded
  using the same class address as class B. Then when some one make
  a call C.invoke and we executed the inlined code B.invoke which
  is the wrong method.
  

Problem conclusion

• This defect will be fixed in:
  5.0.0 SR10
  6.0.0 SR5
  .
  Added code to invalidate the check after class is unloaded.
  .
  To obtain the fix:
  Install build 20090506 or later
  

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:

  IZ50209 PK99653

Fix information

• Fixed component name

  JAVA 5 JIT

• Fixed component ID

  620500124

Applicable component levels

• R500 PSN

     UP