IV20267: MULTIPLE THREADS STUCK IN PARKED STATE

APAR status

• Closed as program error.

Error description

• This problem is specific to the x86 processor family.
  
  
  Error Message: Multiple threads are parked on the same lock:
  
  
  3XMTHREADINFO      "offerer4" J9VMThread:0x00002AABB8162200,
  j9thread_t:0x00002AABB8158150, java/lang/Thr
  ead:0x00002AAAB046C9A0, state:P, prio=5
  3XMTHREADINFO1            (native thread ID:0x3A3D, native
  priority:0x5, native policy:UNKNOWN)
  3XMTHREADINFO2            (native stack address range
  from:0x00000000420E5000, to:0x0000000042126000, siz
  e:0x41000)
  3XMTHREADBLOCK     Parked on:
  java/util/concurrent/locks/ReentrantLock$NonfairSync@0x00002AAAB
  040D780 Own
  ed by: <unknown>
  3XMTHREADINFO3           Java callstack:
  4XESTACKTRACE                at sun/misc/Unsafe.park(Native
  Method)
  4XESTACKTRACE                at
  java/util/concurrent/locks/LockSupport.park(LockSupport.java:186
  (Compiled
   Code))
  4XESTACKTRACE                at
  java/util/concurrent/locks/AbstractQueuedSynchronizer.parkAndChe
  ckInterru
  pt(AbstractQueuedSynchronizer.java:834(Compiled Code))
  4XESTACKTRACE                at
  java/util/concurrent/locks/AbstractQueuedSynchronizer.acquireQue
  ued(Abstr
  actQueuedSynchronizer.java:867(Compiled Code))
  4XESTACKTRACE                at
  java/util/concurrent/locks/AbstractQueuedSynchronizer.acquire(Ab
  stractQue
  uedSynchronizer.java:1197(Compiled Code))
  4XESTACKTRACE                at
  java/util/concurrent/locks/ReentrantLock$NonfairSync.lock(Reentr
  antLock.j
  ava:214(Compiled Code))
  4XESTACKTRACE                at
  java/util/concurrent/locks/ReentrantLock.lock(ReentrantLock.java
  :290(Comp
  iled Code))
  4XESTACKTRACE                at
  java/util/concurrent/ArrayBlockingQueue.offer(ArrayBlockingQueue
  .java:298
  (Compiled Code))
  4XESTACKTRACE                at Offerer.run(SyncTest.java:137)
  The thread that is supposed to wake all the parked threads is
  also incorrectly stuck in the parked state so all the threads
  remain parked and never wake.
  .
  Stack Trace: N/A
  .
  

Local fix

Problem summary

• The problem occurs when the Java code depends on volatile
  semantics to ensure that the volatile field updates are seen in
  different threads.  The problem is caused by incorrect volatile
  field handling.  A memory fence for a volatile field is missing
  after a write operation due to incorrect JIT patching.
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 SR2
  7.0.0 SR1
  .
  The JVM has been updated to not patch over the fence if the
  field is found to be a volatile.
  

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

• R260 PSY

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