diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 24a907b..63ba00b 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -4277,6 +4277,8 @@
      * @return {@code uid} if the connection is found and the app has permission to observe it
      * (e.g., if it is associated with the calling VPN app's tunnel) or
      * {@link android.os.Process#INVALID_UID} if the connection is not found.
+     * Throws {@link SecurityException} if the caller is not the active VPN for the current user.
+     * Throws {@link IllegalArgumentException} if an unsupported protocol is requested.
      */
     public int getConnectionOwnerUid(int protocol, @NonNull InetSocketAddress local,
             @NonNull InetSocketAddress remote) {
diff --git a/core/java/android/net/InetAddresses.java b/core/java/android/net/InetAddresses.java
index 8e6c69a..01b795e 100644
--- a/core/java/android/net/InetAddresses.java
+++ b/core/java/android/net/InetAddresses.java
@@ -16,6 +16,8 @@
 
 package android.net;
 
+import android.annotation.NonNull;
+
 import libcore.net.InetAddressUtils;
 
 import java.net.InetAddress;
@@ -40,7 +42,7 @@
      * @param address the address to parse.
      * @return true if the supplied address is numeric, false otherwise.
      */
-    public static boolean isNumericAddress(String address) {
+    public static boolean isNumericAddress(@NonNull String address) {
         return InetAddressUtils.isNumericAddress(address);
     }
 
@@ -57,7 +59,7 @@
      * @return an {@link InetAddress} instance corresponding to the address.
      * @throws IllegalArgumentException if {@code address} is not a numeric address.
      */
-    public static InetAddress parseNumericAddress(String address) {
+    public static @NonNull InetAddress parseNumericAddress(@NonNull String address) {
         return InetAddressUtils.parseNumericAddress(address);
     }
 }
diff --git a/core/java/android/net/LinkAddress.java b/core/java/android/net/LinkAddress.java
index 8d779aa..8b01960 100644
--- a/core/java/android/net/LinkAddress.java
+++ b/core/java/android/net/LinkAddress.java
@@ -25,6 +25,7 @@
 import static android.system.OsConstants.RT_SCOPE_SITE;
 import static android.system.OsConstants.RT_SCOPE_UNIVERSE;
 
+import android.annotation.NonNull;
 import android.annotation.SystemApi;
 import android.annotation.TestApi;
 import android.annotation.UnsupportedAppUsage;
@@ -177,7 +178,7 @@
      */
     @SystemApi
     @TestApi
-    public LinkAddress(InetAddress address, int prefixLength) {
+    public LinkAddress(@NonNull InetAddress address, int prefixLength) {
         this(address, prefixLength, 0, 0);
         this.scope = scopeForUnicastAddress(address);
     }
@@ -196,12 +197,12 @@
     /**
      * Constructs a new {@code LinkAddress} from a string such as "192.0.2.5/24" or
      * "2001:db8::1/64". The flags are set to zero and the scope is determined from the address.
-     * @param string The string to parse.
+     * @param address The string to parse.
      * @hide
      */
     @SystemApi
     @TestApi
-    public LinkAddress(String address) {
+    public LinkAddress(@NonNull String address) {
         this(address, 0, 0);
         this.scope = scopeForUnicastAddress(this.address);
     }
@@ -209,7 +210,7 @@
     /**
      * Constructs a new {@code LinkAddress} from a string such as "192.0.2.5/24" or
      * "2001:db8::1/64", with the specified flags and scope.
-     * @param string The string to parse.
+     * @param address The string to parse.
      * @param flags The address flags.
      * @param scope The address scope.
      * @hide
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 90281b7..cc3e6fb 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -5565,6 +5565,8 @@
     }
 
     public void handleUpdateLinkProperties(NetworkAgentInfo nai, LinkProperties newLp) {
+        ensureRunningOnConnectivityServiceThread();
+
         if (getNetworkAgentInfoForNetId(nai.network.netId) != nai) {
             // Ignore updates for disconnected networks
             return;
diff --git a/services/core/java/com/android/server/connectivity/TcpKeepaliveController.java b/services/core/java/com/android/server/connectivity/TcpKeepaliveController.java
index 8a9ac23..65de83b 100644
--- a/services/core/java/com/android/server/connectivity/TcpKeepaliveController.java
+++ b/services/core/java/com/android/server/connectivity/TcpKeepaliveController.java
@@ -16,10 +16,12 @@
 package com.android.server.connectivity;
 
 import static android.net.SocketKeepalive.DATA_RECEIVED;
+import static android.net.SocketKeepalive.ERROR_HARDWARE_UNSUPPORTED;
 import static android.net.SocketKeepalive.ERROR_INVALID_SOCKET;
 import static android.net.SocketKeepalive.ERROR_SOCKET_NOT_IDLE;
 import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_ERROR;
 import static android.os.MessageQueue.OnFileDescriptorEventListener.EVENT_INPUT;
+import static android.system.OsConstants.ENOPROTOOPT;
 import static android.system.OsConstants.FIONREAD;
 import static android.system.OsConstants.IPPROTO_TCP;
 import static android.system.OsConstants.TIOCOUTQ;
@@ -179,12 +181,13 @@
             trw = NetworkUtils.getTcpRepairWindow(fd);
         } catch (ErrnoException e) {
             Log.e(TAG, "Exception reading TCP state from socket", e);
-            try {
-                Os.setsockoptInt(fd, IPPROTO_TCP, TCP_REPAIR, TCP_REPAIR_OFF);
-            } catch (ErrnoException ex) {
-                Log.e(TAG, "Exception while turning off repair mode due to exception", ex);
+            if (e.errno == ENOPROTOOPT) {
+                // ENOPROTOOPT may happen in kernel version lower than 4.8.
+                // Treat it as ERROR_HARDWARE_UNSUPPORTED.
+                throw new InvalidSocketException(ERROR_HARDWARE_UNSUPPORTED, e);
+            } else {
+                throw new InvalidSocketException(ERROR_INVALID_SOCKET, e);
             }
-            throw new InvalidSocketException(ERROR_INVALID_SOCKET, e);
         } finally {
             dropAllIncomingPackets(fd, false);
         }