diff --git a/tests/cts/hostside/app/src/com/android/cts/net/hostside/RemoteSocketFactoryClient.java b/tests/cts/hostside/app/src/com/android/cts/net/hostside/RemoteSocketFactoryClient.java
index 799fe50ebe..80f99b6605 100644
--- a/tests/cts/hostside/app/src/com/android/cts/net/hostside/RemoteSocketFactoryClient.java
+++ b/tests/cts/hostside/app/src/com/android/cts/net/hostside/RemoteSocketFactoryClient.java
@@ -22,11 +22,15 @@ import android.content.Intent;
 import android.content.ServiceConnection;
 import android.os.ConditionVariable;
 import android.os.IBinder;
+import android.os.ParcelFileDescriptor;
 import android.os.RemoteException;
+import android.system.ErrnoException;
+import android.system.Os;
 
 import com.android.cts.net.hostside.IRemoteSocketFactory;
 
 import java.io.FileDescriptor;
+import java.io.IOException;
 
 public class RemoteSocketFactoryClient {
     private static final int TIMEOUT_MS = 5000;
@@ -76,9 +80,14 @@ public class RemoteSocketFactoryClient {
         }
     }
 
-    public FileDescriptor openSocketFd(
-            String host, int port, int timeoutMs) throws RemoteException {
-        return mService.openSocketFd(host, port, timeoutMs).getFileDescriptor();
+    public FileDescriptor openSocketFd(String host, int port, int timeoutMs)
+            throws RemoteException, ErrnoException, IOException {
+        // Dup the filedescriptor so ParcelFileDescriptor's finalizer doesn't garbage collect it
+        // and cause our fd to become invalid. http://b/35927643 .
+        ParcelFileDescriptor pfd = mService.openSocketFd(host, port, timeoutMs);
+        FileDescriptor fd = Os.dup(pfd.getFileDescriptor());
+        pfd.close();
+        return fd;
     }
 
     public String getPackageName() throws RemoteException {
diff --git a/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java b/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
index 12fe625370..075fce69a0 100755
--- a/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
+++ b/tests/cts/hostside/app/src/com/android/cts/net/hostside/VpnTest.java
@@ -476,7 +476,11 @@ public class VpnTest extends InstrumentationTestCase {
     private FileDescriptor openSocketFd(String host, int port, int timeoutMs) throws Exception {
         Socket s = new Socket(host, port);
         s.setSoTimeout(timeoutMs);
-        return ParcelFileDescriptor.fromSocket(s).getFileDescriptor();
+        // Dup the filedescriptor so ParcelFileDescriptor's finalizer doesn't garbage collect it
+        // and cause our fd to become invalid. http://b/35927643 .
+        FileDescriptor fd = Os.dup(ParcelFileDescriptor.fromSocket(s).getFileDescriptor());
+        s.close();
+        return fd;
     }
 
     private FileDescriptor openSocketFdInOtherApp(
@@ -506,7 +510,9 @@ public class VpnTest extends InstrumentationTestCase {
 
     private void assertSocketStillOpen(FileDescriptor fd, String host) throws Exception {
         try {
+            assertTrue(fd.valid());
             sendRequest(fd, host);
+            assertTrue(fd.valid());
         } finally {
             Os.close(fd);
         }
@@ -514,10 +520,12 @@ public class VpnTest extends InstrumentationTestCase {
 
     private void assertSocketClosed(FileDescriptor fd, String host) throws Exception {
         try {
+            assertTrue(fd.valid());
             sendRequest(fd, host);
             fail("Socket opened before VPN connects should be closed when VPN connects");
         } catch (ErrnoException expected) {
             assertEquals(ECONNABORTED, expected.errno);
+            assertTrue(fd.valid());
         } finally {
             Os.close(fd);
         }