runtime/jni/LockTest intermittently hangs on linux-i586/linux-amd64.

Baseline results:
http://sqeweb.sfbay.sun.com/nfs/results/vm/gtee/JDK6/BASELINE/VM/r29/vm/linux-i586/server/mixed/linux-i586_vm_server_mixed_vm.runtime.testlist/analysis.html

The test hangs in the following place:
"main" prio=10 tid=0x08489000 nid=0x210c runnable [0xf733d000]
   java.lang.Thread.State: RUNNABLE
        at java.lang.Thread.yield(Native Method)
        at runtime.jni.LockTest.Bilingual.runTest(Bilingual.java:142)
        at runtime.jni.LockTest.LockTest.runLockTest(LockTest.java:40)
        at runtime.jni.LockTest.LockTest.main(LockTest.java:29)

The problem is in the following code:
Bilingual.java
   130 // Test jni -> bilingual lockqueue migration
   131 lockCount = 0;
   132 Monitor.monitorEnter(obj);
   133 new Thread(new UnlockVerify2()).start();
   134 new Thread(new UnlockVerify2()).start();
   135 new Thread(new UnlockVerify2()).start();
   136 synchronized(obj) {
   137 while(lockCount != 3)
   138 Thread.yield();
   139 Monitor.monitorExit(obj);
   140 }
   141 while(lockCount > 0)
   142 Thread.yield();
   143 lockqueueJNIToBilingual = "pass";

Fastdebug VM build fails with the following assertion:
# Internal Error (/BUILD_AREA/jdk7/hotspot/src/share/vm/runtime/synchronizer.cpp:3696), pid=27983, tid=4142402448
# assert(false) failed: Non-balanced monitor enter/exit!
[2010-10-21T18:00:39.18] ------------------------------------------------
[2010-10-21T18:00:39.18] Java only simple contention pass
[2010-10-21T18:00:39.18] Java vs JNI simple contention pass
[2010-10-21T18:00:39.18] Java wait/notify pass
[2010-10-21T18:00:39.18] Java wait/notifyAll pass
[2010-10-21T18:00:39.18] JNI only simple contention pass
[2010-10-21T18:00:39.18] JNI vs Java simple contention pass
[2010-10-21T18:00:39.18] JNI unlock of unowned monitor pass
[2010-10-21T18:00:39.18] JNI unlock of another thread's monitor pass
[2010-10-21T18:00:39.18] JNI unlock of java only lock fail
[2010-10-21T18:00:39.18] JNI unlock of reentrant java only lock fail
[2010-10-21T18:00:39.18] JNI wait/notify pass
[2010-10-21T18:00:39.18] JNI wait/notifyAll pass
[2010-10-21T18:00:39.18] # Test level exit status: 151