fix: resolve race condition in task executor

jadx-core/src/main/java/jadx/core/utils/tasks/TaskExecutor.java

@@ -46,8 +46,9 @@ public class TaskExecutor implements ITaskExecutor {
 	private final AtomicInteger progress = new AtomicInteger(0);
 	private final AtomicBoolean running = new AtomicBoolean(false);
 	private final AtomicBoolean terminating = new AtomicBoolean(false);
-	private int tasksCount = 0;
+	private final Object executorSync = new Object();
 	private @Nullable ExecutorService executor;
+	private int tasksCount = 0;
 
 	@Override
 	public void addParallelTasks(List<? extends Runnable> parallelTasks) {
@@ -94,15 +95,35 @@ public class TaskExecutor implements ITaskExecutor {
 
 	@Override
 	public void execute() {
-		if (running.get() || executor != null) {
-			throw new IllegalStateException("Already executing");
+		synchronized (executorSync) {
+			if (running.get() || executor != null) {
+				throw new IllegalStateException("Already executing");
+			}
+			executor = Executors.newFixedThreadPool(1, Utils.simpleThreadFactory("task-s"));
+			running.set(true);
+			terminating.set(false);
+			progress.set(0);
+			executor.execute(this::runStages);
+		}
+	}
+
+	private void stopExecution() {
+		synchronized (executorSync) {
+			running.set(false);
+			terminating.set(true);
+			if (executor != null) {
+				executor.shutdown();
+				executor = null;
+			}
+		}
+	}
+
+	@Override
+	public void awaitTermination() {
+		ExecutorService activeExecutor = executor;
+		if (activeExecutor != null && running.get()) {
+			awaitExecutorTermination(activeExecutor);
 		}
-		running.set(true);
-		progress.set(0);
-		terminating.set(false);
-		executor = Executors.newFixedThreadPool(1, Utils.simpleThreadFactory("task-s"));
-		executor.execute(this::runStages);
-		executor.shutdown();
 	}
 
 	@Override
@@ -125,15 +146,6 @@ public class TaskExecutor implements ITaskExecutor {
 		return executor;
 	}
 
-	@Override
-	public void awaitTermination() {
-		if (executor == null || !running.get()) {
-			// already terminated
-			return;
-		}
-		awaitExecutorTermination(executor);
-	}
-
 	private void runStages() {
 		try {
 			for (ExecStage stage : stages) {
@@ -156,8 +168,7 @@ public class TaskExecutor implements ITaskExecutor {
 				}
 			}
 		} finally {
-			running.set(false);
-			executor = null;
+			stopExecution();
 		}
 	}