diff --git a/services/core/java/com/android/server/ambientcontext/AmbientContextManagerService.java b/services/core/java/com/android/server/ambientcontext/AmbientContextManagerService.java
index 9e23363680eaa..46e60014b851a 100644
--- a/services/core/java/com/android/server/ambientcontext/AmbientContextManagerService.java
+++ b/services/core/java/com/android/server/ambientcontext/AmbientContextManagerService.java
@@ -56,11 +56,11 @@ import java.io.FileDescriptor;
 import java.io.PrintWriter;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Objects;
 import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * System service for managing {@link AmbientContextEvent}s.
@@ -600,7 +600,7 @@ public class AmbientContextManagerService extends
             unregisterObserver_enforcePermission();
             assertCalledByPackageOwner(callingPackage);
 
-            synchronized (mExistingClientRequests) {
+            synchronized (mLock) {
                 for (ClientRequest cr : mExistingClientRequests) {
                     if (cr.getPackageName().equals(callingPackage)) {
                         AmbientContextManagerPerUserService service =