IZ74022: JAVA CLASS WITH MANY METHODS CAUSES CRASH IN JIT-COMPILED CODE

APAR status

• Closed as program error.

Error description

• Error Message: The Java 5 or Java 6 JVM on z/OS or z/Linux
  receives a SIGSEGV, SIGILL, or ABEND while executing a method
  that has been compiled by the just-in-time compiler. The crash
  is triggered by a branch to a memory location that does not
  contain executable code.
  .
  Stack Trace: N/A
  .
  

Local fix

• This issue can be worked around by preventing the JIT from
  compiling the affected method, using the -Xjit:exclude={...}
  option. If the affected method is not known, the only workaround
  is to disable the JIT compiler using the -Xint option. Note that
  the latter will cause severe performance degradation.
  

Problem summary

• The crash occurs when a JIT-compiled method attempts to call a
  virtual method in a very large class (e.g. one that has more
  than 4096 methods on 64-bit z/OS or z/Linux). On some 390
  hardware, the JIT compiler generates incorrect instructions for
  such method calls, resulting in a wild jump.
  

Problem conclusion

• This defect will be fixed in:
  6.0.0 SR8 FP1
  5.0.0 SR12
  .
  The JIT compiler has been updated to generate correct
  instructions for calls to method in very large classes on all
  hardware types.
  .
  To obtain the fix:
  Install build 20100421 or later
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  IZ74021

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  JAVA 5 JIT

• Fixed component ID

  620500124

Applicable component levels

• R500 PSN

     UP