2 files changed, 7 insertions, 3 deletions
diff --git a/packages/Vcn/service-b/src/com/android/server/vcn/Vcn.java b/packages/Vcn/service-b/src/com/android/server/vcn/Vcn.java
index 369ef6ae6a3f..97f86b1bff5b 100644
--- a/packages/Vcn/service-b/src/com/android/server/vcn/Vcn.java
+++ b/packages/Vcn/service-b/src/com/android/server/vcn/Vcn.java
@@ -209,6 +209,8 @@ public class Vcn extends Handler {
         this(vcnContext, subscriptionGroup, config, snapshot, vcnCallback, new Dependencies());
     }
 
+    // WARNING: This constructor executes on the binder thread. Thread safety MUST be ensured when
+    // accessing data within this constructor and any methods called from here.
     @VisibleForTesting(visibility = Visibility.PRIVATE)
     public Vcn(
             @NonNull VcnContext vcnContext,
diff --git a/packages/Vcn/service-b/src/com/android/server/vcn/VcnNetworkProvider.java b/packages/Vcn/service-b/src/com/android/server/vcn/VcnNetworkProvider.java
index 99c848f53c39..38fcf09145d9 100644
--- a/packages/Vcn/service-b/src/com/android/server/vcn/VcnNetworkProvider.java
+++ b/packages/Vcn/service-b/src/com/android/server/vcn/VcnNetworkProvider.java
@@ -36,7 +36,6 @@ import android.net.vcn.VcnGatewayConnectionConfig;
 import android.os.Build;
 import android.os.Handler;
 import android.os.Looper;
-import android.util.ArraySet;
 import android.util.IndentingPrintWriter;
 import android.util.Slog;
 
@@ -46,6 +45,7 @@ import com.android.modules.utils.HandlerExecutor;
 
 import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executor;
 
 /**
@@ -56,12 +56,14 @@ import java.util.concurrent.Executor;
  *
  * @hide
  */
+// TODO(b/388919146): Implement a more generic solution to prevent concurrent modifications on
+// mListeners and mRequests
 // TODO(b/374174952): Replace VANILLA_ICE_CREAM with BAKLAVA after Android B finalization
 @TargetApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
 public class VcnNetworkProvider extends NetworkProvider {
     private static final String TAG = VcnNetworkProvider.class.getSimpleName();
 
-    private final Set<NetworkRequestListener> mListeners = new ArraySet<>();
+    private final Set<NetworkRequestListener> mListeners = ConcurrentHashMap.newKeySet();
 
     private final Context mContext;
     private final Handler mHandler;
@@ -72,7 +74,7 @@ public class VcnNetworkProvider extends NetworkProvider {
      *
      * <p>NetworkRequests are immutable once created, and therefore can be used as stable keys.
      */
-    private final Set<NetworkRequest> mRequests = new ArraySet<>();
+    private final Set<NetworkRequest> mRequests = ConcurrentHashMap.newKeySet();
 
     public VcnNetworkProvider(@NonNull Context context, @NonNull Looper looper) {
         this(context, looper, new Dependencies());