Fixes HttpClient Content.Source reads from arbitrary threads

jetty-core/jetty-client/src/main/java/org/eclipse/jetty/client/transport/HttpReceiver.java

@@ -67,7 +67,7 @@ public abstract class HttpReceiver
 {
     private static final Logger LOG = LoggerFactory.getLogger(HttpReceiver.class);
 
-    private final SerializedInvoker invoker = new SerializedInvoker();
+    private final SerializedInvoker invoker = new SerializedInvoker(HttpReceiver.class);
     private final HttpChannel channel;
     private ResponseState responseState = ResponseState.IDLE;
     private NotifiableContentSource contentSource;
@@ -731,6 +731,7 @@ public void onDataAvailable()
         {
             if (LOG.isDebugEnabled())
                 LOG.debug("onDataAvailable on {}", this);
+            invoker.assertCurrentThreadInvoking();
             // The onDataAvailable() method is only ever called
             // by the invoker so avoid using the invoker again.
             invokeDemandCallback(false);
@@ -755,6 +756,8 @@ private void processDemand()
             if (LOG.isDebugEnabled())
                 LOG.debug("Processing demand on {}", this);
 
+            invoker.assertCurrentThreadInvoking();
+
             Content.Chunk current;
             try (AutoLock ignored = lock.lock())
             {
@@ -794,9 +797,14 @@ private void invokeDemandCallback(boolean invoke)
             try
             {
                 if (invoke)
+                {
                     invoker.run(demandCallback);
+                }
                 else
+                {
+                    invoker.assertCurrentThreadInvoking();
                     demandCallback.run();
+                }
             }
             catch (Throwable x)
             {

jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/MultiPart.java

@@ -564,7 +564,7 @@ public String toString()
     public abstract static class AbstractContentSource implements Content.Source, Closeable
     {
         private final AutoLock lock = new AutoLock();
-        private final SerializedInvoker invoker = new SerializedInvoker();
+        private final SerializedInvoker invoker = new SerializedInvoker(AbstractContentSource.class);
         private final Queue<Part> parts = new ArrayDeque<>();
         private final String boundary;
         private final ByteBuffer firstBoundary;

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/AsyncContent.java

@@ -50,7 +50,7 @@ public String toString()
     };
 
     private final AutoLock.WithCondition lock = new AutoLock.WithCondition();
-    private final SerializedInvoker invoker = new SerializedInvoker();
+    private final SerializedInvoker invoker = new SerializedInvoker(AsyncContent.class);
     private final Queue<Content.Chunk> chunks = new ArrayDeque<>();
     private Content.Chunk persistentFailure;
     private boolean readClosed;

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ByteBufferContentSource.java

@@ -31,7 +31,7 @@
 public class ByteBufferContentSource implements Content.Source
 {
     private final AutoLock lock = new AutoLock();
-    private final SerializedInvoker invoker = new SerializedInvoker();
+    private final SerializedInvoker invoker = new SerializedInvoker(ByteBufferContentSource.class);
     private final long length;
     private final Collection<ByteBuffer> byteBuffers;
     private Iterator<ByteBuffer> iterator;

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ChunksContentSource.java

@@ -33,7 +33,7 @@
 public class ChunksContentSource implements Content.Source
 {
     private final AutoLock lock = new AutoLock();
-    private final SerializedInvoker invoker = new SerializedInvoker();
+    private final SerializedInvoker invoker = new SerializedInvoker(ChunksContentSource.class);
     private final long length;
     private final Collection<Content.Chunk> chunks;
     private Iterator<Content.Chunk> iterator;

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/ContentSourceTransformer.java

@@ -39,7 +39,7 @@ public abstract class ContentSourceTransformer implements Content.Source
 
     protected ContentSourceTransformer(Content.Source rawSource)
     {
-        this(rawSource, new SerializedInvoker());
+        this(rawSource, new SerializedInvoker(ContentSourceTransformer.class));
     }
 
     protected ContentSourceTransformer(Content.Source rawSource, SerializedInvoker invoker)

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/InputStreamContentSource.java

@@ -38,7 +38,7 @@
 public class InputStreamContentSource implements Content.Source
 {
     private final AutoLock lock = new AutoLock();
-    private final SerializedInvoker invoker = new SerializedInvoker();
+    private final SerializedInvoker invoker = new SerializedInvoker(InputStreamContentSource.class);
     private final InputStream inputStream;
     private ByteBufferPool.Sized bufferPool;
     private Runnable demandCallback;

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/content/PathContentSource.java

@@ -41,7 +41,7 @@ public class PathContentSource implements Content.Source
     // TODO in 12.1.x reimplement this class based on ByteChannelContentSource
 
     private final AutoLock lock = new AutoLock();
-    private final SerializedInvoker invoker = new SerializedInvoker();
+    private final SerializedInvoker invoker = new SerializedInvoker(PathContentSource.class);
     private final Path path;
     private final long length;
     private final ByteBufferPool byteBufferPool;

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/internal/ByteChannelContentSource.java

@@ -39,7 +39,7 @@
 public class ByteChannelContentSource implements Content.Source
 {
     private final AutoLock lock = new AutoLock();
-    private final SerializedInvoker _invoker = new SerializedInvoker();
+    private final SerializedInvoker _invoker = new SerializedInvoker(ByteChannelContentSource.class);
     private final ByteBufferPool.Sized _byteBufferPool;
     private ByteChannel _byteChannel;
     private final long _offset;

jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/internal/HttpChannelState.java

@@ -128,8 +128,8 @@ public HttpChannelState(ConnectionMetaData connectionMetaData)
     {
         _connectionMetaData = connectionMetaData;
         // The SerializedInvoker is used to prevent infinite recursion of callbacks calling methods calling callbacks etc.
-        _readInvoker = new HttpChannelSerializedInvoker();
-        _writeInvoker = new HttpChannelSerializedInvoker();
+        _readInvoker = new HttpChannelSerializedInvoker(HttpChannelState.class.getSimpleName() + "_readInvoker");
+        _writeInvoker = new HttpChannelSerializedInvoker(HttpChannelState.class.getSimpleName() + "_writeInvoker");
     }
 
     @Override
@@ -1812,6 +1812,11 @@ private void completing()
 
     private class HttpChannelSerializedInvoker extends SerializedInvoker
     {
+        public HttpChannelSerializedInvoker(String name)
+        {
+            super(name);
+        }
+
         @Override
         protected void onError(Runnable task, Throwable failure)
         {

jetty-core/jetty-util/src/main/java/org/eclipse/jetty/util/thread/SerializedExecutor.java

@@ -27,7 +27,7 @@
  */
 public class SerializedExecutor implements Executor
 {
-    private final SerializedInvoker _invoker = new SerializedInvoker()
+    private final SerializedInvoker _invoker = new SerializedInvoker(SerializedExecutor.class)
     {
         @Override
         protected void onError(Runnable task, Throwable t)

jetty-core/jetty-util/src/main/java/org/eclipse/jetty/util/thread/SerializedInvoker.java

@@ -13,8 +13,12 @@
 
 package org.eclipse.jetty.util.thread;
 
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.util.concurrent.atomic.AtomicReference;
 
+import org.eclipse.jetty.util.component.Dumpable;
 import org.eclipse.jetty.util.thread.Invocable.InvocationType;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -35,6 +39,51 @@ public class SerializedInvoker
     private static final Logger LOG = LoggerFactory.getLogger(SerializedInvoker.class);
 
     private final AtomicReference<Link> _tail = new AtomicReference<>();
+    private final String _name;
+    private volatile Thread _invokerThread;
+
+    /**
+     * Create a new instance whose name is {@code anonymous}.
+     */
+    public SerializedInvoker()
+    {
+        this("anonymous");
+    }
+
+    /**
+     * Create a new instance whose name is derived from the given class.
+     * @param nameFrom the class to use as a name.
+     */
+    public SerializedInvoker(Class<?> nameFrom)
+    {
+        this(nameFrom.getSimpleName());
+    }
+
+    /**
+     * Create a new instance with the given name.
+     * @param name the name.
+     */
+    public SerializedInvoker(String name)
+    {
+        _name = name;
+    }
+
+    /**
+     * @return whether the current thread is currently executing a task using this invoker
+     */
+    boolean isCurrentThreadInvoking()
+    {
+        return _invokerThread == Thread.currentThread();
+    }
+
+    /**
+     * @throws IllegalStateException when the current thread is not currently executing a task using this invoker
+     */
+    public void assertCurrentThreadInvoking() throws IllegalStateException
+    {
+        if (!isCurrentThreadInvoking())
+            throw new IllegalStateException();
+    }
 
     /**
      * Arrange for a task to be invoked, mutually excluded from other tasks.
@@ -59,7 +108,7 @@ public Runnable offer(Runnable task)
             {
                 // Wrap the given task with another one that's going to delegate run() to the wrapped task while the
                 // wrapper's toString() returns a description of the place in code where SerializedInvoker.run() was called.
-                task = new NamedRunnable(task, deriveTaskName(task));
+                task = new NamedRunnable(task);
             }
         }
         Link link = new Link(task);
@@ -72,18 +121,6 @@ public Runnable offer(Runnable task)
         return null;
     }
 
-    protected String deriveTaskName(Runnable task)
-    {
-        StackTraceElement[] stackTrace = new Exception().getStackTrace();
-        for (StackTraceElement stackTraceElement : stackTrace)
-        {
-            String className = stackTraceElement.getClassName();
-            if (!className.equals(SerializedInvoker.class.getName()) && !className.equals(getClass().getName()))
-                return "Queued at " + stackTraceElement;
-        }
-        return task.toString();
-    }
-
     /**
      * Arrange for tasks to be invoked, mutually excluded from other tasks.
      * @param tasks The tasks to invoke
@@ -116,8 +153,8 @@ public void run(Runnable task)
         if (todo != null)
             todo.run();
         else
-            if (LOG.isDebugEnabled())
-                LOG.debug("Queued link in {}", this);
+        if (LOG.isDebugEnabled())
+            LOG.debug("Queued link in {}", this);
     }
 
     /**
@@ -131,22 +168,22 @@ public void run(Runnable... tasks)
         if (todo != null)
             todo.run();
         else
-            if (LOG.isDebugEnabled())
-                LOG.debug("Queued links in {}", this);
+        if (LOG.isDebugEnabled())
+            LOG.debug("Queued links in {}", this);
     }
 
     @Override
     public String toString()
     {
-        return String.format("%s@%x{tail=%s}", getClass().getSimpleName(), hashCode(), _tail);
+        return String.format("%s@%x{name=%s,tail=%s,invoker=%s}", getClass().getSimpleName(), hashCode(), _name, _tail, _invokerThread);
     }
 
     protected void onError(Runnable task, Throwable t)
     {
         LOG.warn("Serialized invocation error", t);
     }
 
-    private class Link implements Runnable, Invocable
+    private class Link implements Runnable, Invocable, Dumpable
     {
         private final Runnable _task;
         private final AtomicReference<Link> _next = new AtomicReference<>();
@@ -156,6 +193,24 @@ public Link(Runnable task)
             _task = task;
         }
 
+        @Override
+        public void dump(Appendable out, String indent) throws IOException
+        {
+            if (_task instanceof NamedRunnable nr)
+            {
+                StringWriter sw = new StringWriter();
+                nr.stack.printStackTrace(new PrintWriter(sw));
+                Dumpable.dumpObjects(out, indent, nr.toString(), sw.toString());
+            }
+            else
+            {
+                Dumpable.dumpObjects(out, indent, _task);
+            }
+            Link link = _next.get();
+            if (link != null)
+                link.dump(out, indent);
+        }
+
         @Override
         public InvocationType getInvocationType()
         {
@@ -186,6 +241,7 @@ public void run()
             {
                 if (LOG.isDebugEnabled())
                     LOG.debug("Running link {} of {}", link, SerializedInvoker.this);
+                _invokerThread = Thread.currentThread();
                 try
                 {
                     link._task.run();
@@ -196,6 +252,12 @@ public void run()
                         LOG.debug("Failed while running link {} of {}", link, SerializedInvoker.this, t);
                     onError(link._task, t);
                 }
+                finally
+                {
+                    // _invokerThread must be nulled before calling link.next() as
+                    // once the latter has executed, another thread can enter Link.run().
+                    _invokerThread = null;
+                }
                 link = link.next();
                 if (link == null && LOG.isDebugEnabled())
                     LOG.debug("Next link is null, execution is over in {}", SerializedInvoker.this);
@@ -209,10 +271,35 @@ public String toString()
         }
     }
 
-    private record NamedRunnable(Runnable delegate, String name) implements Runnable
+    private class NamedRunnable implements Runnable
     {
         private static final Logger LOG = LoggerFactory.getLogger(NamedRunnable.class);
 
+        private final Runnable delegate;
+        private final String name;
+        private final Throwable stack;
+
+        public NamedRunnable(Runnable delegate)
+        {
+            this.delegate = delegate;
+            this.stack = new Throwable();
+            this.name = deriveTaskName(delegate, stack);
+        }
+
+        protected String deriveTaskName(Runnable task, Throwable stack)
+        {
+            StackTraceElement[] stackTrace = stack.getStackTrace();
+            for (StackTraceElement stackTraceElement : stackTrace)
+            {
+                String className = stackTraceElement.getClassName();
+                if (!className.equals(SerializedInvoker.class.getName()) &&
+                    !className.equals(SerializedInvoker.this.getClass().getName()) &&
+                    !className.equals(getClass().getName()))
+                    return "Queued by " + Thread.currentThread().getName() + " at " + stackTraceElement;
+            }
+            return task.toString();
+        }
+
         @Override
         public void run()
         {