IJ15120: CRASH IN JIT COMPILED CODE DUE TO LACK OF RANGE CHECK

APAR status

• Closed as program error.

Error description

• Error Message: Segmentation Error
  .
  Stack Trace: The crash location will be in code generated into
  memory by the Java JIT compiler - the location will vary but the
  faulting instruction will be near a conditional branch.
  .
  

Local fix

• The problem can be avoided by using -Xjit:disableInlining. Using
  this option globally will have a large negative impact on
  performance.
  To limit the performance impact it is recommended you apply the
  disableInlining option to the failing method(s) only by using
  the following syntax:
  -Xjit:{*class.method*}(disableInlining)
  Using disableInlining on a single method is unlikely to result
  in a noticeable impact on performance.
  

Problem summary

• When a method is inlined by the JIT compiler, the generated code
  needs to have a safety check to ensure that the method inlined
  at compile-time is the correct method to run when the code is
  actually running. This check involves reading an entry at a
  fixed offset from the class's virtual function table. The
  compiler did not range check the offset against the size of the
  lookup table which could lead to a crash reading invalid memory
  in certain rare circumstances.
  

Problem conclusion

• A range check has been added to the inline method check to
  ensure we do not read invalid memory.
  .
  This APAR will be fixed in the following Java Releases:
   8 SR5 FP31 (8.0.5.31)
  .
  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