search

oracle / visualvm

VisualVM is an All-in-One Java Troubleshooting Tool
https://visualvm.github.io/
Other
2.79k stars 297 forks source link

[HeapViewer] failed to show threads when heap dump contains virtual threads (JDK 22) #539

Closed alexmenkov closed 6 months ago

alexmenkov commented 6 months ago

JDK 22 adds support of virtual threads in heap dumps (thread objects/stack traces/stack references): https://bugs.openjdk.org/browse/JDK-8316691 https://bugs.openjdk.org/browse/JDK-8299426

VisualVM fails to show threads if heap dump contains virtual threads:

The reason is JavaThreadsProvider expects Thread object has non-null "holder" field. VirtualThread objects have null "holder" field (virtual threads are always daemon threads, they have fixed priority that cannot be changed, thread status is stored in VirtualThread object).

thurka commented 6 months ago

I am not able to reproduce it. Where is 'heap dump contains virtual threads'?

alexmenkov commented 6 months ago

Myheapdump_vt.zip

alexmenkov commented 6 months ago

I've attached sample hprof file which contains virtual threads

thurka commented 6 months ago

Thanks, I will take a look.

thurka commented 6 months ago

I fixed NPE. In attached heap dump I now see two entries for Virtual thread [#29]/runnable@ForkJoinPool-1-worker-1. The first is in the middle with stack trace and the second is the last without stack trace. This look strange to me. Can you confirm that the attached heap dump is correct? 

"main" prio=5 tid=1 TIMED_WAITING
    at java.lang.Thread.sleepNanos0(Native Method)
    at java.lang.Thread.sleepNanos(Thread.java:491)
       local variable: java.lang.Thread#2
    at java.lang.Thread.sleep(Thread.java:522)
    at jdk.test.lib.apps.LingeredApp.main(LingeredApp.java:630)
       local variable: java.lang.String[]#22
       local variable: java.lang.String#2561
       local variable: sun.nio.fs.WindowsPath#1
       local variable: jdk.test.lib.apps.LingeredApp$SteadyStateLock#1
       local variable: jdk.test.lib.apps.LingeredApp$SteadyStateLock#1
    at MyTest2Targ.runTest(MyTest2.java:148)
       local variable: MyTest2Targ#1
       local variable: java.lang.String[]#22
       local variable: MyTest2Targ$VthreadMounted#1
       local variable: MyTest2Targ$Pthread#1
    at MyTest2Targ.main(MyTest2.java:159)
       local variable: java.lang.String[]#22
       local variable: MyTest2Targ#1

"Reference Handler" daemon prio=10 tid=9 RUNNABLE
    at java.lang.ref.Reference.waitForReferencePendingList(Native Method)
    at java.lang.ref.Reference.processPendingReferences(Reference.java:246)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:208)
       local variable: java.lang.ref.Reference$ReferenceHandler#1

"Finalizer" daemon prio=8 tid=10 WAITING
    at java.lang.Object.wait0(Native Method)
    at java.lang.Object.wait(Object.java:375)
       local variable: java.lang.ref.NativeReferenceQueue$Lock#1
    at java.lang.Object.wait(Object.java:348)
       local variable: java.lang.ref.NativeReferenceQueue$Lock#1
    at java.lang.ref.NativeReferenceQueue.await(NativeReferenceQueue.java:48)
       local variable: java.lang.ref.NativeReferenceQueue#1
    at java.lang.ref.ReferenceQueue.remove0(ReferenceQueue.java:158)
       local variable: java.lang.ref.NativeReferenceQueue#1
    at java.lang.ref.NativeReferenceQueue.remove(NativeReferenceQueue.java:89)
       local variable: java.lang.ref.NativeReferenceQueue#1
       local variable: java.lang.ref.NativeReferenceQueue$Lock#1
    at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:173)
       local variable: java.lang.ref.Finalizer$FinalizerThread#1
       local variable: java.lang.System$2#1

"Signal Dispatcher" daemon prio=9 tid=11 RUNNABLE

"Attach Listener" daemon prio=5 tid=12 RUNNABLE

"Notification Thread" daemon prio=9 tid=19 RUNNABLE

"Common-Cleaner" daemon prio=8 tid=20 TIMED_WAITING
    at jdk.internal.misc.Unsafe.park(Native Method)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:269)
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject#6
       local variable: jdk.internal.misc.InnocuousThread#1
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1847)
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject#6
       local variable: java.util.concurrent.TimeUnit#3
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionNode#1
    at java.lang.ref.ReferenceQueue.await(ReferenceQueue.java:71)
       local variable: java.lang.ref.ReferenceQueue#4
    at java.lang.ref.ReferenceQueue.remove0(ReferenceQueue.java:143)
       local variable: java.lang.ref.ReferenceQueue#4
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:218)
       local variable: java.lang.ref.ReferenceQueue#4
    at jdk.internal.ref.CleanerImpl.run(CleanerImpl.java:140)
       local variable: jdk.internal.ref.CleanerImpl#1
       local variable: jdk.internal.misc.InnocuousThread#1
       local variable: jdk.internal.misc.InnocuousThread#1
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: jdk.internal.misc.InnocuousThread#1
       local variable: class java.lang.Thread
       local variable: jdk.internal.ref.CleanerImpl#1
    at java.lang.Thread.run(Thread.java:1570)
       local variable: jdk.internal.misc.InnocuousThread#1
       local variable: jdk.internal.ref.CleanerImpl#1
       local variable: class java.lang.Thread
    at jdk.internal.misc.InnocuousThread.run(InnocuousThread.java:186)
       local variable: jdk.internal.misc.InnocuousThread#1

Virtual Thread [#29]/runnable@ForkJoinPool-1-worker-1
    at MyTest2Targ$VthreadMounted.run(MyTest2.java:99)
       local variable: MyTest2Targ$VthreadMounted#1
       local variable: MyTest2Targ$VThreadMountedReferenced#1
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: java.lang.VirtualThread#6
       local variable: class java.lang.Thread
       local variable: MyTest2Targ$VthreadMounted#1
    at java.lang.VirtualThread.run(VirtualThread.java:321)
       local variable: java.lang.VirtualThread#6
       local variable: MyTest2Targ$VthreadMounted#1
       local variable: class java.lang.Thread
    at java.lang.VirtualThread$VThreadContinuation$1.run(VirtualThread.java:201)
       local variable: java.lang.VirtualThread$VThreadContinuation$1#6
    at jdk.internal.vm.Continuation.enter0(Continuation.java:320)
       local variable: java.lang.VirtualThread$VThreadContinuation#6
    at jdk.internal.vm.Continuation.enter(Continuation.java:312)
       local variable: java.lang.VirtualThread$VThreadContinuation#6

"ForkJoinPool-1-worker-1" daemon prio=5 tid=22 RUNNABLE
    at jdk.internal.vm.Continuation.run(Continuation.java:248)
       local variable: java.lang.VirtualThread$VThreadContinuation#6
       local variable: jdk.internal.misc.CarrierThread#1
    at java.lang.VirtualThread.runContinuation(VirtualThread.java:237)
       local variable: java.lang.VirtualThread#6
    at java.lang.VirtualThread$$Lambda+0x00000248a6057a28.run(<unresolved string 0x0>)
       local variable: java.lang.VirtualThread$$Lambda+0x00000248a6057a28#6
    at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.compute(ForkJoinTask.java:1726)
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
    at java.util.concurrent.ForkJoinTask$RunnableExecuteAction.compute(ForkJoinTask.java:1717)
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
    at java.util.concurrent.ForkJoinTask$InterruptibleTask.exec(ForkJoinTask.java:1641)
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
       local variable: jdk.internal.misc.CarrierThread#1
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
    at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:507)
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
    at java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1491)
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#2
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#1
    at java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:2073)
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue[]#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#1
       local variable: java.util.concurrent.ForkJoinTask[]#1
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
       local variable: java.util.concurrent.ForkJoinTask$RunnableExecuteAction#1
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:2035)
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#2
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:187)
       local variable: jdk.internal.misc.CarrierThread#1
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#2

"ForkJoinPool-1-worker-2" daemon prio=5 tid=23 WAITING
    at jdk.internal.misc.Unsafe.park(Native Method)
    at java.util.concurrent.ForkJoinPool.awaitWork(ForkJoinPool.java:2145)
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#3
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue[]#2
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:2036)
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#3
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:187)
       local variable: jdk.internal.misc.CarrierThread#2
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#3

"ForkJoinPool-1-worker-3" daemon prio=5 tid=24 WAITING
    at jdk.internal.misc.Unsafe.park(Native Method)
    at java.util.concurrent.ForkJoinPool.awaitWork(ForkJoinPool.java:2145)
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#4
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue[]#2
    at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:2036)
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#4
    at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:187)
       local variable: jdk.internal.misc.CarrierThread#3
       local variable: java.util.concurrent.ForkJoinPool#2
       local variable: java.util.concurrent.ForkJoinPool$WorkQueue#4

"Thread-0" prio=5 tid=30 WAITING
    at jdk.internal.misc.Unsafe.park(Native Method)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:221)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.lang.Thread#1
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:754)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#6
       local variable: java.lang.Thread#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#5
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#6
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1099)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:230)
       local variable: java.util.concurrent.CountDownLatch#1
    at MyTest2Targ.awaitToStop(MyTest2.java:121)
       local variable: MyTest2Targ#1
    at MyTest2Targ$Pthread.run(MyTest2.java:111)
       local variable: MyTest2Targ$Pthread#1
       local variable: MyTest2Targ$PThreadReferenced#1
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: java.lang.Thread#1
       local variable: class java.lang.Thread
       local variable: MyTest2Targ$Pthread#1
    at java.lang.Thread.run(Thread.java:1570)
       local variable: java.lang.Thread#1
       local variable: MyTest2Targ$Pthread#1
       local variable: class java.lang.Thread

"SteadyStateThread" prio=5 tid=31 BLOCKED
    at jdk.test.lib.apps.LingeredApp.steadyState(LingeredApp.java:567)
       local variable: jdk.test.lib.apps.LingeredApp$SteadyStateLock#1
       local variable: jdk.test.lib.apps.LingeredApp$SteadyStateLock#1
    at jdk.test.lib.apps.LingeredApp$1.run(LingeredApp.java:573)
       local variable: jdk.test.lib.apps.LingeredApp$1#1

Virtual Thread [#21]/parking
    at jdk.internal.vm.Continuation.yield0(Continuation.java:360)
       local variable: java.lang.VirtualThread$VThreadContinuation#1
       local variable: jdk.internal.vm.ContinuationScope#1
    at jdk.internal.vm.Continuation.yield(Continuation.java:351)
       local variable: jdk.internal.vm.ContinuationScope#1
       local variable: java.lang.VirtualThread$VThreadContinuation#1
       local variable: java.lang.VirtualThread$VThreadContinuation#1
    at java.lang.VirtualThread.yieldContinuation(VirtualThread.java:441)
       local variable: java.lang.VirtualThread#1
    at java.lang.VirtualThread.park(VirtualThread.java:588)
       local variable: java.lang.VirtualThread#1
    at java.lang.System$2.parkVirtualThread(System.java:2643)
       local variable: java.lang.System$2#1
       local variable: java.lang.VirtualThread#1
       local variable: java.lang.VirtualThread#1
    at jdk.internal.misc.VirtualThreads.park(VirtualThreads.java:54)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:219)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.lang.VirtualThread#1
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:754)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#1
       local variable: java.lang.VirtualThread#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$ExclusiveNode#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#1
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1099)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:230)
       local variable: java.util.concurrent.CountDownLatch#1
    at MyTest2Targ.awaitToStop(MyTest2.java:121)
       local variable: MyTest2Targ#1
    at MyTest2Targ$VthreadUnmounted.run(MyTest2.java:86)
       local variable: MyTest2Targ$VthreadUnmounted#1
       local variable: MyTest2Targ$VThreadUnmountedReferenced#1
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: java.lang.VirtualThread#1
       local variable: class java.lang.Thread
       local variable: MyTest2Targ$VthreadUnmounted#1
    at java.lang.VirtualThread.run(VirtualThread.java:321)
       local variable: java.lang.VirtualThread#1
       local variable: MyTest2Targ$VthreadUnmounted#1
       local variable: class java.lang.Thread
    at java.lang.VirtualThread$VThreadContinuation$1.run(VirtualThread.java:201)
       local variable: java.lang.VirtualThread$VThreadContinuation$1#1
    at jdk.internal.vm.Continuation.enter0(Continuation.java:320)
       local variable: java.lang.VirtualThread$VThreadContinuation#1
    at jdk.internal.vm.Continuation.enter(Continuation.java:312)
       local variable: java.lang.VirtualThread$VThreadContinuation#1

Virtual Thread [#25]/parking
    at jdk.internal.vm.Continuation.yield0(Continuation.java:360)
       local variable: java.lang.VirtualThread$VThreadContinuation#2
       local variable: jdk.internal.vm.ContinuationScope#1
    at jdk.internal.vm.Continuation.yield(Continuation.java:351)
       local variable: jdk.internal.vm.ContinuationScope#1
       local variable: java.lang.VirtualThread$VThreadContinuation#2
       local variable: java.lang.VirtualThread$VThreadContinuation#2
    at java.lang.VirtualThread.yieldContinuation(VirtualThread.java:441)
       local variable: java.lang.VirtualThread#2
    at java.lang.VirtualThread.park(VirtualThread.java:588)
       local variable: java.lang.VirtualThread#2
    at java.lang.System$2.parkVirtualThread(System.java:2643)
       local variable: java.lang.System$2#1
       local variable: java.lang.VirtualThread#2
       local variable: java.lang.VirtualThread#2
    at jdk.internal.misc.VirtualThreads.park(VirtualThreads.java:54)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:219)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.lang.VirtualThread#2
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:754)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#2
       local variable: java.lang.VirtualThread#2
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#2
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1099)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:230)
       local variable: java.util.concurrent.CountDownLatch#1
    at MyTest2Targ.awaitToStop(MyTest2.java:121)
       local variable: MyTest2Targ#1
    at MyTest2Targ$VthreadUnmounted.run(MyTest2.java:86)
       local variable: MyTest2Targ$VthreadUnmounted#2
       local variable: MyTest2Targ$VThreadUnmountedReferenced#2
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: java.lang.VirtualThread#2
       local variable: class java.lang.Thread
       local variable: MyTest2Targ$VthreadUnmounted#2
    at java.lang.VirtualThread.run(VirtualThread.java:321)
       local variable: java.lang.VirtualThread#2
       local variable: MyTest2Targ$VthreadUnmounted#2
       local variable: class java.lang.Thread
    at java.lang.VirtualThread$VThreadContinuation$1.run(VirtualThread.java:201)
       local variable: java.lang.VirtualThread$VThreadContinuation$1#2
    at jdk.internal.vm.Continuation.enter0(Continuation.java:320)
       local variable: java.lang.VirtualThread$VThreadContinuation#2
    at jdk.internal.vm.Continuation.enter(Continuation.java:312)
       local variable: java.lang.VirtualThread$VThreadContinuation#2

Virtual Thread [#26]/parking
    at jdk.internal.vm.Continuation.yield0(Continuation.java:360)
       local variable: java.lang.VirtualThread$VThreadContinuation#3
       local variable: jdk.internal.vm.ContinuationScope#1
    at jdk.internal.vm.Continuation.yield(Continuation.java:351)
       local variable: jdk.internal.vm.ContinuationScope#1
       local variable: java.lang.VirtualThread$VThreadContinuation#3
       local variable: java.lang.VirtualThread$VThreadContinuation#3
    at java.lang.VirtualThread.yieldContinuation(VirtualThread.java:441)
       local variable: java.lang.VirtualThread#3
    at java.lang.VirtualThread.park(VirtualThread.java:588)
       local variable: java.lang.VirtualThread#3
    at java.lang.System$2.parkVirtualThread(System.java:2643)
       local variable: java.lang.System$2#1
       local variable: java.lang.VirtualThread#3
       local variable: java.lang.VirtualThread#3
    at jdk.internal.misc.VirtualThreads.park(VirtualThreads.java:54)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:219)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.lang.VirtualThread#3
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:754)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#3
       local variable: java.lang.VirtualThread#3
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#2
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#3
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1099)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:230)
       local variable: java.util.concurrent.CountDownLatch#1
    at MyTest2Targ.awaitToStop(MyTest2.java:121)
       local variable: MyTest2Targ#1
    at MyTest2Targ$VthreadUnmounted.run(MyTest2.java:86)
       local variable: MyTest2Targ$VthreadUnmounted#3
       local variable: MyTest2Targ$VThreadUnmountedReferenced#3
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: java.lang.VirtualThread#3
       local variable: class java.lang.Thread
       local variable: MyTest2Targ$VthreadUnmounted#3
    at java.lang.VirtualThread.run(VirtualThread.java:321)
       local variable: java.lang.VirtualThread#3
       local variable: MyTest2Targ$VthreadUnmounted#3
       local variable: class java.lang.Thread
    at java.lang.VirtualThread$VThreadContinuation$1.run(VirtualThread.java:201)
       local variable: java.lang.VirtualThread$VThreadContinuation$1#3
    at jdk.internal.vm.Continuation.enter0(Continuation.java:320)
       local variable: java.lang.VirtualThread$VThreadContinuation#3
    at jdk.internal.vm.Continuation.enter(Continuation.java:312)
       local variable: java.lang.VirtualThread$VThreadContinuation#3

Virtual Thread [#27]/parking
    at jdk.internal.vm.Continuation.yield0(Continuation.java:360)
       local variable: java.lang.VirtualThread$VThreadContinuation#4
       local variable: jdk.internal.vm.ContinuationScope#1
    at jdk.internal.vm.Continuation.yield(Continuation.java:351)
       local variable: jdk.internal.vm.ContinuationScope#1
       local variable: java.lang.VirtualThread$VThreadContinuation#4
       local variable: java.lang.VirtualThread$VThreadContinuation#4
    at java.lang.VirtualThread.yieldContinuation(VirtualThread.java:441)
       local variable: java.lang.VirtualThread#4
    at java.lang.VirtualThread.park(VirtualThread.java:588)
       local variable: java.lang.VirtualThread#4
    at java.lang.System$2.parkVirtualThread(System.java:2643)
       local variable: java.lang.System$2#1
       local variable: java.lang.VirtualThread#4
       local variable: java.lang.VirtualThread#4
    at jdk.internal.misc.VirtualThreads.park(VirtualThreads.java:54)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:219)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.lang.VirtualThread#4
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:754)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#4
       local variable: java.lang.VirtualThread#4
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#3
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#4
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1099)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:230)
       local variable: java.util.concurrent.CountDownLatch#1
    at MyTest2Targ.awaitToStop(MyTest2.java:121)
       local variable: MyTest2Targ#1
    at MyTest2Targ$VthreadUnmounted.run(MyTest2.java:86)
       local variable: MyTest2Targ$VthreadUnmounted#4
       local variable: MyTest2Targ$VThreadUnmountedReferenced#4
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: java.lang.VirtualThread#4
       local variable: class java.lang.Thread
       local variable: MyTest2Targ$VthreadUnmounted#4
    at java.lang.VirtualThread.run(VirtualThread.java:321)
       local variable: java.lang.VirtualThread#4
       local variable: MyTest2Targ$VthreadUnmounted#4
       local variable: class java.lang.Thread
    at java.lang.VirtualThread$VThreadContinuation$1.run(VirtualThread.java:201)
       local variable: java.lang.VirtualThread$VThreadContinuation$1#4
    at jdk.internal.vm.Continuation.enter0(Continuation.java:320)
       local variable: java.lang.VirtualThread$VThreadContinuation#4
    at jdk.internal.vm.Continuation.enter(Continuation.java:312)
       local variable: java.lang.VirtualThread$VThreadContinuation#4

Virtual Thread [#28]/parking
    at jdk.internal.vm.Continuation.yield0(Continuation.java:360)
       local variable: java.lang.VirtualThread$VThreadContinuation#5
       local variable: jdk.internal.vm.ContinuationScope#1
    at jdk.internal.vm.Continuation.yield(Continuation.java:351)
       local variable: jdk.internal.vm.ContinuationScope#1
       local variable: java.lang.VirtualThread$VThreadContinuation#5
       local variable: java.lang.VirtualThread$VThreadContinuation#5
    at java.lang.VirtualThread.yieldContinuation(VirtualThread.java:441)
       local variable: java.lang.VirtualThread#5
    at java.lang.VirtualThread.park(VirtualThread.java:588)
       local variable: java.lang.VirtualThread#5
    at java.lang.System$2.parkVirtualThread(System.java:2643)
       local variable: java.lang.System$2#1
       local variable: java.lang.VirtualThread#5
       local variable: java.lang.VirtualThread#5
    at jdk.internal.misc.VirtualThreads.park(VirtualThreads.java:54)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:219)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.lang.VirtualThread#5
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:754)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#5
       local variable: java.lang.VirtualThread#5
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#4
       local variable: java.util.concurrent.locks.AbstractQueuedSynchronizer$SharedNode#5
    at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireSharedInterruptibly(AbstractQueuedSynchronizer.java:1099)
       local variable: java.util.concurrent.CountDownLatch$Sync#1
    at java.util.concurrent.CountDownLatch.await(CountDownLatch.java:230)
       local variable: java.util.concurrent.CountDownLatch#1
    at MyTest2Targ.awaitToStop(MyTest2.java:121)
       local variable: MyTest2Targ#1
    at MyTest2Targ$VthreadUnmounted.run(MyTest2.java:86)
       local variable: MyTest2Targ$VthreadUnmounted#5
       local variable: MyTest2Targ$VThreadUnmountedReferenced#5
    at java.lang.Thread.runWith(Thread.java:1583)
       local variable: java.lang.VirtualThread#5
       local variable: class java.lang.Thread
       local variable: MyTest2Targ$VthreadUnmounted#5
    at java.lang.VirtualThread.run(VirtualThread.java:321)
       local variable: java.lang.VirtualThread#5
       local variable: MyTest2Targ$VthreadUnmounted#5
       local variable: class java.lang.Thread
    at java.lang.VirtualThread$VThreadContinuation$1.run(VirtualThread.java:201)
       local variable: java.lang.VirtualThread$VThreadContinuation$1#5
    at jdk.internal.vm.Continuation.enter0(Continuation.java:320)
       local variable: java.lang.VirtualThread$VThreadContinuation#5
    at jdk.internal.vm.Continuation.enter(Continuation.java:312)
       local variable: java.lang.VirtualThread$VThreadContinuation#5

Virtual Thread [#29]/runnable@ForkJoinPool-1-worker-1
alexmenkov commented 6 months ago

@thurka The thread dump looks good. Duplicate of the Virtual thread [#29] is bug in the JDK heap dumper. Will fix it.

thurka commented 6 months ago

Will fix it.

Great. I want to separate normal and virual threads in threads view (or create separate virtual threads view).

thurka commented 6 months ago

NPE fixed in master.