IJ24076: JAVA JIT: CRASH IN JIT COMPILED CODE ON SYSTEMZ

APAR status

• Closed as program error.

Error description

• Error Message: A SEGV/OC4 is reported while executing JIT
  compiled code.
  .
  Stack Trace: N/A
  .
  The problem can only happen on the SystemZ architecture (zOS or
  zLinux). In order to hit this problem there must be a Java class
  that has at least 4097 methods defined in it.
  This problem can not occur on POWER or x86 versions of the JVM.
  

Local fix

• The only way to avoid the problem is to disable the JIT compiler
  (-Xint) which will have a major effect on performance.
  

Problem summary

• The JVM needs to patch JIT compiled code for virtual call
  sequences where the target method has yet to be resolved when
  the compilation occurred. When the call is first executed at
  run-time the JIT will resolve the target method and patch the
  JIT generated code with the correct virtual function table
  offset. The JIT would incorrectly generate a instruction that
  only allows for a 16bit offset to be patched in at runt-time.
  This would cause a patching failure when the table offset was
  determined at run-time to be greater then what can fit in a
  16bit integer.
  

Problem conclusion

• The JIT was modified so that it generated an instruction that
  has a 32bit space for patching in the resolved virtual function
  table offsets.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR6 FP10  (8.0.6.10)
  .
  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:

Fix information

• Fixed component name

  JIT

• Fixed component ID

  620700124

Applicable component levels