diff --git a/core/java/android/net/ConnectivityDiagnosticsManager.java b/core/java/android/net/ConnectivityDiagnosticsManager.java
index 275e38c..704f31d 100644
--- a/core/java/android/net/ConnectivityDiagnosticsManager.java
+++ b/core/java/android/net/ConnectivityDiagnosticsManager.java
@@ -711,6 +711,13 @@
      * not currently registered. If a ConnectivityDiagnosticsCallback instance is registered with
      * multiple NetworkRequests, an IllegalArgumentException will be thrown.
      *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * callbacks in {@link ConnectivityManager}. Registering a callback with this method will count
+     * toward this limit. If this limit is exceeded, an exception will be thrown. To avoid hitting
+     * this issue and to conserve resources, make sure to unregister the callbacks with
+     * {@link #unregisterConnectivityDiagnosticsCallback}.
+     *
      * @param request The NetworkRequest that will be used to match with Networks for which
      *     callbacks will be fired
      * @param e The Executor to be used for running the callback method invocations
@@ -718,6 +725,7 @@
      *     System
      * @throws IllegalArgumentException if the same callback instance is registered with multiple
      *     NetworkRequests
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     public void registerConnectivityDiagnosticsCallback(
             @NonNull NetworkRequest request,
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 6b71360..9c994eb 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -2271,27 +2271,6 @@
                 throwException);
     }
 
-    /** {@hide} */
-    public static final void enforceTetherChangePermission(Context context, String callingPkg,
-            String callingAttributionTag) {
-        Preconditions.checkNotNull(context, "Context cannot be null");
-        Preconditions.checkNotNull(callingPkg, "callingPkg cannot be null");
-
-        if (context.getResources().getStringArray(
-                com.android.internal.R.array.config_mobile_hotspot_provision_app).length == 2) {
-            // Have a provisioning app - must only let system apps (which check this app)
-            // turn on tethering
-            context.enforceCallingOrSelfPermission(
-                    android.Manifest.permission.TETHER_PRIVILEGED, "ConnectivityService");
-        } else {
-            int uid = Binder.getCallingUid();
-            // If callingPkg's uid is not same as Binder.getCallingUid(),
-            // AppOpsService throws SecurityException.
-            checkAndNoteWriteSettingsOperation(context, uid, callingPkg,
-                    callingAttributionTag, true /* throwException */);
-        }
-    }
-
     /**
      * Check if the package is a allowed to write settings. This also accounts that such an access
      * happened.
@@ -3855,13 +3834,22 @@
      * or the ability to modify system settings as determined by
      * {@link android.provider.Settings.System#canWrite}.</p>
      *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #registerNetworkCallback} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
      * @param request {@link NetworkRequest} describing this request.
      * @param networkCallback The {@link NetworkCallback} to be utilized for this request. Note
      *                        the callback must not be shared - it uniquely specifies this request.
      *                        The callback is invoked on the default internal Handler.
      * @throws IllegalArgumentException if {@code request} contains invalid network capabilities.
      * @throws SecurityException if missing the appropriate permissions.
-     * @throws RuntimeException if request limit per UID is exceeded.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     public void requestNetwork(@NonNull NetworkRequest request,
             @NonNull NetworkCallback networkCallback) {
@@ -3875,8 +3863,8 @@
      * but runs all the callbacks on the passed Handler.
      *
      * <p>This method has the same permission requirements as
-     * {@link #requestNetwork(NetworkRequest, NetworkCallback)} and throws the same exceptions in
-     * the same conditions.
+     * {@link #requestNetwork(NetworkRequest, NetworkCallback)}, is subject to the same limitations,
+     * and throws the same exceptions in the same conditions.
      *
      * @param request {@link NetworkRequest} describing this request.
      * @param networkCallback The {@link NetworkCallback} to be utilized for this request. Note
@@ -3907,8 +3895,8 @@
      * for that purpose. Calling this method will attempt to bring up the requested network.
      *
      * <p>This method has the same permission requirements as
-     * {@link #requestNetwork(NetworkRequest, NetworkCallback)} and throws the same exceptions in
-     * the same conditions.
+     * {@link #requestNetwork(NetworkRequest, NetworkCallback)}, is subject to the same limitations,
+     * and throws the same exceptions in the same conditions.
      *
      * @param request {@link NetworkRequest} describing this request.
      * @param networkCallback The {@link NetworkCallback} to be utilized for this request. Note
@@ -3934,8 +3922,8 @@
      * on the passed Handler.
      *
      * <p>This method has the same permission requirements as
-     * {@link #requestNetwork(NetworkRequest, NetworkCallback, int)} and throws the same exceptions
-     * in the same conditions.
+     * {@link #requestNetwork(NetworkRequest, NetworkCallback)}, is subject to the same limitations,
+     * and throws the same exceptions in the same conditions.
      *
      * @param request {@link NetworkRequest} describing this request.
      * @param networkCallback The {@link NetworkCallback} to be utilized for this request. Note
@@ -4004,6 +3992,15 @@
      * is unknown prior to bringing up the network so the framework does not
      * know how to go about satisfying a request with these capabilities.
      *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #registerNetworkCallback} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with {@link #unregisterNetworkCallback(PendingIntent)}
+     * or {@link #releaseNetworkRequest(PendingIntent)}.
+     *
      * <p>This method requires the caller to hold either the
      * {@link android.Manifest.permission#CHANGE_NETWORK_STATE} permission
      * or the ability to modify system settings as determined by
@@ -4015,7 +4012,7 @@
      *                  comes from {@link PendingIntent#getBroadcast}. Cannot be null.
      * @throws IllegalArgumentException if {@code request} contains invalid network capabilities.
      * @throws SecurityException if missing the appropriate permissions.
-     * @throws RuntimeException if request limit per UID is exceeded.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     public void requestNetwork(@NonNull NetworkRequest request,
             @NonNull PendingIntent operation) {
@@ -4072,10 +4069,20 @@
      * either the application exits or {@link #unregisterNetworkCallback(NetworkCallback)} is
      * called.
      *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
      * @param request {@link NetworkRequest} describing this request.
      * @param networkCallback The {@link NetworkCallback} that the system will call as suitable
      *                        networks change state.
      *                        The callback is invoked on the default internal Handler.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
     public void registerNetworkCallback(@NonNull NetworkRequest request,
@@ -4089,10 +4096,21 @@
      * either the application exits or {@link #unregisterNetworkCallback(NetworkCallback)} is
      * called.
      *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
+     *
      * @param request {@link NetworkRequest} describing this request.
      * @param networkCallback The {@link NetworkCallback} that the system will call as suitable
      *                        networks change state.
      * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
     public void registerNetworkCallback(@NonNull NetworkRequest request,
@@ -4126,10 +4144,21 @@
      * <p>
      * The request may be released normally by calling
      * {@link #unregisterNetworkCallback(android.app.PendingIntent)}.
+     *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with {@link #unregisterNetworkCallback(PendingIntent)}
+     * or {@link #releaseNetworkRequest(PendingIntent)}.
+     *
      * @param request {@link NetworkRequest} describing this request.
      * @param operation Action to perform when the network is available (corresponds
      *                  to the {@link NetworkCallback#onAvailable} call.  Typically
      *                  comes from {@link PendingIntent#getBroadcast}. Cannot be null.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
     public void registerNetworkCallback(@NonNull NetworkRequest request,
@@ -4151,9 +4180,19 @@
      * will continue to be called until either the application exits or
      * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
      *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
      * @param networkCallback The {@link NetworkCallback} that the system will call as the
      *                        system default network changes.
      *                        The callback is invoked on the default internal Handler.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
     public void registerDefaultNetworkCallback(@NonNull NetworkCallback networkCallback) {
@@ -4165,9 +4204,19 @@
      * will continue to be called until either the application exits or
      * {@link #unregisterNetworkCallback(NetworkCallback)} is called.
      *
+     * <p>To avoid performance issues due to apps leaking callbacks, the system will limit the
+     * number of outstanding requests to 100 per app (identified by their UID), shared with
+     * all variants of this method, of {@link #requestNetwork} as well as
+     * {@link ConnectivityDiagnosticsManager#registerConnectivityDiagnosticsCallback}.
+     * Requesting a network with this method will count toward this limit. If this limit is
+     * exceeded, an exception will be thrown. To avoid hitting this issue and to conserve resources,
+     * make sure to unregister the callbacks with
+     * {@link #unregisterNetworkCallback(NetworkCallback)}.
+     *
      * @param networkCallback The {@link NetworkCallback} that the system will call as the
      *                        system default network changes.
      * @param handler {@link Handler} to specify the thread upon which the callback will be invoked.
+     * @throws RuntimeException if the app already has too many callbacks registered.
      */
     @RequiresPermission(android.Manifest.permission.ACCESS_NETWORK_STATE)
     public void registerDefaultNetworkCallback(@NonNull NetworkCallback networkCallback,
@@ -4259,7 +4308,6 @@
      *                  Cannot be null.
      */
     public void unregisterNetworkCallback(@NonNull PendingIntent operation) {
-        checkPendingIntentNotNull(operation);
         releaseNetworkRequest(operation);
     }
 
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index e859abc..320f3fb 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -6428,7 +6428,7 @@
             final boolean shouldFilter = requiresVpnIsolation(nai, newNc, nai.linkProperties);
             final String iface = nai.linkProperties.getInterfaceName();
             // For VPN uid interface filtering, old ranges need to be removed before new ranges can
-            // be added, due to the range being expanded and stored as invidiual UIDs. For example
+            // be added, due to the range being expanded and stored as individual UIDs. For example
             // the UIDs might be updated from [0, 99999] to ([0, 10012], [10014, 99999]) which means
             // prevRanges = [0, 99999] while newRanges = [0, 10012], [10014, 99999]. If prevRanges
             // were added first and then newRanges got removed later, there would be only one uid