ClosedByInterruptException while computing Path to GC Root in Heap Viewer

[thurka]

VisualVM throws java.nio.channels.ClosedByInterruptException while computing the nearest GC root / path to GC root for an instance in the Heap Viewer.

VisualVM 2.2.1, JDK 17.

  java.nio.channels.ClosedByInterruptException
      at java.base/java.nio.channels.spi.AbstractInterruptibleChannel.end(AbstractInterruptibleChannel.java:199)
      at java.base/sun.nio.ch.FileChannelImpl.endBlocking(FileChannelImpl.java:171)
      at java.base/sun.nio.ch.FileChannelImpl.write(FileChannelImpl.java:293)
      at org.graalvm.visualvm.lib.jfluid.heap.AbstractLongMap$LongMemoryMappedData.force(AbstractLongMap.java:542)
      at org.graalvm.visualvm.lib.jfluid.heap.AbstractLongMap$AbstractData.writeToStream(AbstractLongMap.java:265)
      at org.graalvm.visualvm.lib.jfluid.heap.AbstractLongMap.writeToStream(AbstractLongMap.java:175)
      at org.graalvm.visualvm.lib.jfluid.heap.LongMap.writeToStream(LongMap.java:310)
      at org.graalvm.visualvm.lib.jfluid.heap.HprofHeap.writeToStream(HprofHeap.java:361)
      at org.graalvm.visualvm.lib.jfluid.heap.HprofHeap.writeToFile(HprofHeap.java:335)
      at org.graalvm.visualvm.lib.jfluid.heap.NearestGCRoot.computeGCRoots(NearestGCRoot.java:128)
      at org.graalvm.visualvm.lib.jfluid.heap.NearestGCRoot.getNearestGCRootPointer(NearestGCRoot.java:87)
      at org.graalvm.visualvm.lib.jfluid.heap.HprofHeap.getNearestGCRootPointer(HprofHeap.java:862)
      at org.graalvm.visualvm.lib.jfluid.heap.InstanceDump.getNearestGCRootPointer(InstanceDump.java:87)
      at org.graalvm.visualvm.heapviewer.java.impl.PathToGCRootPlugin.computeInstanceRoots(PathToGCRootPlugin.java:366)
      at org.graalvm.visualvm.heapviewer.java.impl.PathToGCRootPlugin$1.computeData(PathToGCRootPlugin.java:193)
      at org.graalvm.visualvm.heapviewer.ui.TreeTableView$1.lazilyComputeChildren(TreeTableView.java:147)
      at org.graalvm.visualvm.heapviewer.model.HeapViewerNode$1.doInBackground(HeapViewerNode.java:179)
      at javax.swing.SwingWorker$1.call(SwingWorker.java:304)
      at java.util.concurrent.FutureTask.run(FutureTask.java:264)
      at javax.swing.SwingWorker.run(SwingWorker.java:343)
      at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
      at java.lang.Thread.run(Thread.java:842)

[thurka]

HeapOperations.initializeGCRoots() uses the first heap instance as a dummy trigger for GC-root computation. If that first instance is itself a GC root, NearestGCRoot.getNearestGCRootPointer() returns immediately and does not compute GC-root paths for the heap. HeapOperations still marks GC roots as initialized.

Later, the real GC-root computation is triggered from the GC Root view’s lazy SwingWorker. If that worker is interrupted while cache data is being persisted, FileChannel.write() can throw ClosedByInterruptException.

Steps To Reproduce

1. Open a large heap dump.
2. Run on Linux, macOS Apple Silicon
3. Use a heap dump where the first instance returned by heap.getAllInstancesIterator().next() is a GC root.
4. Open the GC Root view for a non-root object or class.
5. While GC-root computation is still running, interrupt the view computation by changing selection, reloading the view, sorting/filtering, closing the view, or otherwise resetting the tree.
6. ClosedByInterruptException will be thrown from AbstractLongMap$LongMemoryMappedData.force() during cache persistence.

[thurka]

FIxed in master.