IV61659: JAVA JIT COMPILATION THREAD NOT RELEASING CLASS TABLE LOCK CAUSI NG APPLICATION TO HANG

APAR status

• Closed as program error.

Error description

• Error Message: N/A
  .
  Stack Trace: N/A
  .
  A Java application hangs. The javacore dump shows:
  
  (1) The VM class table is locked by a JIT compilation thread:
  
  2LKREGMON    VM class table lock (0x7F836E70): Flat locked by "J
  IT Compilation Thread" (0x7F813A00), entry count 1
  3LKWAITERQ      Waiting to enter:
  3LKWAITER          "Signal Dispatcher" (0x7F836F00)
  3LKWAITER          "HungThreadDetectorForDeferrable Alarm" (0x7F
  839500)
  3LKWAITER          "LT=0:P=821261:O=0:port=9109" (0x7F83F800)
  .
  .
  .
  (60+ threads waiting to enter)
  
  (2) The JIT compilation thread itself is waiting for another
  lock:
  
  2LKREGMON    JIT-CompilationQueueMonitor lock (0x7F832C20): <uno
  wned>
  3LKNOTIFYQ      Waiting to be notified
  3LKWAITNOTIFY      "JIT Compilation Thread" (0x7F813A00)
  

Local fix

Problem summary

• Under rare circumstances, the JIT compilation thread locks the
  VM class table but does not release it before finishing a
  compilation.
  

Problem conclusion

• The JIT compiler has been updated to release the VM class table
  lock in such situations.
  .
  This APAR will be fixed in the following Java Releases:
     6    SR16 FP1  (6.0.16.1)
     6 R1 SR8  FP1  (6.1.8.1)
     7    SR7  FP1  (7.0.7.1)
     7 R1 SR1  FP1  (7.1.1.1)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, Java maintenance is available
  from:
             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

• R600 PSY

     UP

• R260 PSY

     UP

• R130 PSY

     UP