Prevent spurious concurrency related errors

jbachorik · jbachorik · commit cec69320d5e2 · 2022-10-08T20:06:06.000+02:00
diff --git a/btrace-agent/src/main/java/org/openjdk/btrace/agent/RemoteClient.java b/btrace-agent/src/main/java/org/openjdk/btrace/agent/RemoteClient.java
@@ -237,7 +237,9 @@ public void onCommand(Command cmd) throws IOException {
     try {
       boolean isConnected = true;
       try {
-        output.reset();
+        synchronized (output) {
+          output.reset();
+        }
       } catch (SocketException e) {
         isConnected = false;
       }
@@ -285,9 +287,11 @@ private boolean dispatchCommand(Command cmd, boolean isConnected) {
           {
             ((DisconnectCommand) cmd).setProbeId(id.toString());
             if (output != null) {
-              WireIO.write(output, cmd);
-              output.flush();
-              output.close();
+              synchronized (output) {
+                WireIO.write(output, cmd);
+                output.flush();
+                output.close();
+              }
               oosUpdater.compareAndSet(this, output, null);
             }
             if (input != null) {
@@ -327,7 +331,9 @@ protected void closeAll() throws IOException {
 
     ObjectOutputStream output = oos;
     if (output != null) {
-      output.close();
+      synchronized (output) {
+        output.close();
+      }
       oosUpdater.compareAndSet(this, output, null);
     }
     ObjectInputStream input = ois;
