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8350765: Need to pin when accessing thread container from virtual thread

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Reviewed-by: vklang, jpai
This commit is contained in:
Alan Bateman 2025-05-13 13:35:40 +00:00
parent 48d2acb386
commit fa419489d3
6 changed files with 69 additions and 44 deletions
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8
src/java.base/share/classes/java/lang/Thread.java
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@ -1,5 +1,5 @@
/*
* Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1994, 2025, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -1409,7 +1409,7 @@ public class Thread implements Runnable {
// start thread
boolean started = false;
container.onStart(this); // may throw
container.add(this); // may throw
try {
// scoped values may be inherited
inheritScopedValueBindings(container);
@ -1418,7 +1418,7 @@ public class Thread implements Runnable {
started = true;
} finally {
if (!started) {
container.onExit(this);
container.remove(this);
}
}
}
@ -1487,7 +1487,7 @@ public class Thread implements Runnable {
// notify container that thread is exiting
ThreadContainer container = threadContainer();
if (container != null) {
container.onExit(this);
container.remove(this);
}
}

4
src/java.base/share/classes/java/lang/VirtualThread.java
View File

@ -664,7 +664,7 @@ final class VirtualThread extends BaseVirtualThread {
// notify container
if (notifyContainer) {
threadContainer().onExit(this);
threadContainer().remove(this);
}
// clear references to thread locals
@ -692,7 +692,7 @@ final class VirtualThread extends BaseVirtualThread {
boolean addedToContainer = false;
boolean started = false;
try {
container.onStart(this); // may throw
container.add(this); // may throw
addedToContainer = true;
// scoped values may be inherited

18
src/java.base/share/classes/java/lang/ref/ReferenceQueue.java
View File

@ -27,7 +27,6 @@ package java.lang.ref;
import java.util.function.Consumer;
import jdk.internal.misc.VM;
import jdk.internal.vm.Continuation;
import jdk.internal.vm.ContinuationSupport;
/**
@ -145,19 +144,6 @@ public class ReferenceQueue<T> {
}
}
private boolean tryDisablePreempt() {
if (Thread.currentThread().isVirtual() && ContinuationSupport.isSupported()) {
Continuation.pin();
return true;
} else {
return false;
}
}
private void enablePreempt() {
Continuation.unpin();
}
/**
* Polls this queue to see if a reference object is available. If one is
* available without further delay then it is removed from the queue and
@ -173,13 +159,13 @@ public class ReferenceQueue<T> {
// Prevent a virtual thread from being preempted as this could potentially
// deadlock with a carrier that is polling the same reference queue.
boolean disabled = tryDisablePreempt();
ContinuationSupport.pinIfSupported();
try {
synchronized (lock) {
return poll0();
}
} finally {
if (disabled) enablePreempt();
ContinuationSupport.unpinIfSupported();
}
}

20
src/java.base/share/classes/jdk/internal/vm/ContinuationSupport.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2022, 2025, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -50,5 +50,23 @@ public class ContinuationSupport {
}
}
/**
* Pins the current continuation if the VM has continuations support.
*/
public static void pinIfSupported() {
if (isSupported()) {
Continuation.pin();
}
}
/**
* Unpins the current continuation if the VM has continuations support.
*/
public static void unpinIfSupported() {
if (isSupported()) {
Continuation.unpin();
}
}
private static native boolean isSupported0();
}

53
src/java.base/share/classes/jdk/internal/vm/ThreadContainer.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2021, 2023, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2021, 2025, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -76,24 +76,49 @@ public abstract class ThreadContainer extends StackableScope {
public abstract Stream<Thread> threads();
/**
* Invoked by Thread::start before the given Thread is started.
* Invoked by {@code add} to add a thread to this container before it starts.
*/
public void onStart(Thread thread) {
// do nothing
protected void onStart(Thread thread) {
}
/**
* Invoked when a Thread terminates or starting it fails.
*
* For a platform thread, this method is invoked by the thread itself when it
* terminates. For a virtual thread, this method is invoked on its carrier
* after the virtual thread has terminated.
*
* If starting the Thread failed then this method is invoked on the thread
* that invoked onStart.
* Invoked by {@code remove} to remove a thread from this container when it
* terminates (or failed to start).
*/
public void onExit(Thread thread) {
// do nothing
protected void onExit(Thread thread) {
}
/**
* Adds a thread to this container. This method should be invoked before the
* thread executes.
*/
public final void add(Thread thread) {
// Prevent a virtual thread from being preempted as this could potentially
// deadlock when scheduled to continue and all carriers are blocked adding
// or removing virtual threads.
ContinuationSupport.pinIfSupported();
try {
onStart(thread);
} finally {
ContinuationSupport.unpinIfSupported();
}
}
/**
* Remove a thread from this container. This method can be invoked by the thread
* itself as it terminates, or it can be invoked by another thread after the given
* thread has terminated (or failed to start).
*/
public final void remove(Thread thread) {
// Prevent a virtual thread from being preempted as this could potentially
// deadlock when scheduled to continue and all carriers are blocked adding
// or removing virtual threads.
ContinuationSupport.pinIfSupported();
try {
onExit(thread);
} finally {
ContinuationSupport.unpinIfSupported();
}
}
/**

10
src/java.base/windows/classes/sun/nio/fs/WindowsSecurity.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2008, 2024, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2008, 2025, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -25,7 +25,6 @@
package sun.nio.fs;
import jdk.internal.vm.Continuation;
import jdk.internal.vm.ContinuationSupport;
import static sun.nio.fs.WindowsNativeDispatcher.*;
@ -106,9 +105,7 @@ class WindowsSecurity {
final boolean needToRevert = elevated;
// prevent yielding with privileges
if (ContinuationSupport.isSupported())
Continuation.pin();
ContinuationSupport.pinIfSupported();
return () -> {
try {
if (token != 0L) {
@ -126,8 +123,7 @@ class WindowsSecurity {
}
} finally {
LocalFree(pLuid);
if (ContinuationSupport.isSupported())
Continuation.unpin();
ContinuationSupport.unpinIfSupported();
}
};
}