IV01668: CRASH IN THREAD UNPARK

APAR status

• Closed as program error.

Error description

• Error Message: j> 13:51:06 Unhandled exception
  j> 13:51:06 Type=Segmentation error vmState=0x7fe78f78
  j> 13:51:06 J9Generic_Signal_Number=00000004
  Signal_Number=0000000b Error_Value=00000000 Signal_Code=00000002
  j> 13:51:06 Handler1=00F571C0 Handler2=00299D20
  InaccessibleAddress=00740289
  j> 13:51:06 EDI=007402DD ESI=00740069 EAX=E5FFF0E9 EBX=00E1A374
  j> 13:51:06 ECX=0000007D EDX=0000006D
  j> 13:51:06 EIP=00E0E64B ES=007B DS=007B ESP=6FDF6090
  j> 13:51:06 EFlags=00210206 CS=0073 SS=007B EBP=6FDF60A8
  j> 13:51:06
  Module=/tmp/pxi3270/ibm-java-i386-70/jre/lib/i386/default/libj9t
  hr26.so
  j> 13:51:06 Module_base_address=00E0B000 Symbol=j9thread_unpark
  j> 13:51:06 Symbol_address=00E0E610
  j> 13:51:06 Target=2_60_20110219_076062 (Linux
  2.6.32-71.14.1.el6.i686)
  .
  Stack Trace: 1XMCURTHDINFO  Current thread
  NULL           ----------------------
  3XMTHREADINFO      "Pooled Thread #740 running
  tests.com.ibm.jtc.concurrent.CopyOnWriteArraySetTest"
  J9VMThread:0x746B7F00, j9thread_t:0x70022AD0,
  java/lang/Thread:0x785CF8B8, state:R, prio=5
  3XMTHREADINFO1            (native thread ID:0x7C1E, native
  priority:0x5, native policy:UNKNOWN)
  3XMTHREADINFO2            (native stack address range
  from:0x6FDB7000, to:0x6FDF8000, size:0x41000)
  3XMTHREADINFO3           Java callstack:
  4XESTACKTRACE                at sun/misc/Unsafe.unpark(Native
  Method)
  4XESTACKTRACE                at
  java/util/concurrent/locks/LockSupport.unpark(LockSupport.java:1
  52)
  4XESTACKTRACE                at
  java/util/concurrent/locks/AbstractQueuedSynchronizer.unparkSucc
  essor(AbstractQueuedSynchronizer.java:662)
  4XESTACKTRACE                at
  java/util/concurrent/locks/AbstractQueuedSynchronizer.release(Ab
  stractQueuedSynchronizer.java:1263)
  4XESTACKTRACE                at
  java/util/concurrent/locks/ReentrantLock.unlock(ReentrantLock.ja
  va:460)
  4XESTACKTRACE                at
  java/util/concurrent/CopyOnWriteArrayList.addIfAbsent(CopyOnWrit
  eArrayList.java:602)
  4XESTACKTRACE                at
  java/util/concurrent/CopyOnWriteArraySet.add(CopyOnWriteArraySet
  .java:248)
  4XESTACKTRACE                at
  tests/com/ibm/jtc/concurrent/CopyOnWriteArraySetTest.testStress(
  CopyOnWriteArraySetTest.java:297)
  4XESTACKTRACE                at
  sun/reflect/GeneratedMethodAccessor46.invoke(Bytecode PC:36)
  4XESTACKTRACE                at
  sun/reflect/DelegatingMethodAccessorImpl.invoke(DelegatingMethod
  AccessorImpl.java:43)
  4XESTACKTRACE                at
  java/lang/reflect/Method.invoke(Method.java:613)
  4XESTACKTRACE                at
  junit/framework/TestCase.runTest(TestCase.java:168)
  4XESTACKTRACE                at
  junit/framework/TestCase.runBare(TestCase.java:134)
  4XESTACKTRACE                at
  junit/framework/TestResult$1.protect(TestResult.java:110)
  4XESTACKTRACE                at
  junit/framework/TestResult.runProtected(TestResult.java:128)
  4XESTACKTRACE                at
  junit/framework/TestResult.run(TestResult.java:113)
  4XESTACKTRACE                at
  junit/framework/TestCase.run(TestCase.java:124)
  4XESTACKTRACE                at
  junit/framework/TestSuite.runTest(TestSuite.java:243)
  4XESTACKTRACE                at
  junit/framework/TestSuite.run(TestSuite.java:238)
  4XESTACKTRACE                at
  com/ibm/jtc/test/jltf/workunitadapters/JUnitWorkUnit.runWork(JUn
  itWorkUnit.java:370)
  4XESTACKTRACE                at
  com/ibm/jtc/test/jltf/threads/WorkUnitRunner.run(WorkUnitRunner.
  java:113)
  4XESTACKTRACE                at
  com/ibm/jtc/test/jltf/threads/pooling/PooledRunnable.runWork(Poo
  ledRunnable.java:156)
  4XESTACKTRACE                at
  com/ibm/jtc/test/jltf/threads/pooling/PooledRunnable.getAndRunWo
  rk(PooledRunnable.java:122)
  4XESTACKTRACE                at
  com/ibm/jtc/test/jltf/threads/pooling/PooledRunnable.run(PooledR
  unnable.java:79)
  4XESTACKTRACE                at
  com/ibm/jtc/test/jltf/threads/PooledLangThreadFactory$JavaLangPo
  oledThread.run(PooledLangThreadFactory.java:152)
  .
  The crash would only occur if garbage collection moved the
  object for the thread that was being parked at the same time as
  the thread was being unparked which is generally rare.  It was
  only seen with a test that stressed park/unpark.
  

Local fix

Problem summary

• A crash would occur if garbage collection moved the object for
  the thread that was being parked at the same time as the thread
  was being unparked which is generally rare.  It was only seen
  with a test that stressed park/unpark.
  

Problem conclusion

• This defect will be fixed in:
  6.0.1 GA FP1
  .
  The JVM has been updated so that if the object is moved, unpark
  is aware of the new location and no crash occurs
  .
  To obtain the fix:
  Install build 20110308 or later
  

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

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels

• R260 PSY

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