IJ18838: HANG IN THE JIT MODULE ATTEMPTING TO RECLAIM RUNTIME ASSUMPTIONS

APAR status

• Closed as program error.

Error description

• Error Message: There is a hang in libj9jit*.so when attempting
  to reclaim and deallocate runtime assumptions during application
  execution.
  .
  Stack Trace:
  RuntimeAssumption::dequeueFromListOfAssumptionsForJittedBody()
  ()
  TR_RuntimeAssumptionTable::reclaimMarkedAssumptionsFromRAT(int)
  ...
  .
  Other failures are also possible, particularly crashes involving
  walking the iprofiler data linked lists.
  
  The problem is long standing but due to recent changes is most
  commonly seen in 8.0.5.40
  

Local fix

• A 100% work-around is not available, but the frequency of
  failures can be reduced by setting the following environment
  variable before starting the JVM
  
  TR_forceAggressiveRATCleaning=1
  

Problem summary

• The problem is caused by a double free of JIT persistent memory
  in a time window between compensating a specific kind of runtime
  assumption and deallocating it.
  

Problem conclusion

• The JIT has been updated to prevent the double free and thus fix
  the hang issues.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP41  (8.0.5.41)
     7    SR10 FP55 (7.0.10.55)
     7 R1 SR4 FP55  (7.1.4.55)
  .
  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