From 21b89197a982c6dc63f0bcc0d9ccfc8cad4828ac Mon Sep 17 00:00:00 2001
From: Kathy Chen <kxchen@google.com>
Date: Mon, 1 May 2023 11:19:44 -0700
Subject: [PATCH] [AC] Fix NPE. If the client sends multiple unregister
 requests at the same time, the client request could be null before the next
 request is processed.

Bug: 278891267
Test: make
Change-Id: I7ff41338ab638ce40ef618bc306cc25f0939f023
---
 .../server/ambientcontext/AmbientContextManagerService.java   | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/ambientcontext/AmbientContextManagerService.java b/services/core/java/com/android/server/ambientcontext/AmbientContextManagerService.java
index 46e60014b851a..9e23363680eaa 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 (mLock) {
+            synchronized (mExistingClientRequests) {
                 for (ClientRequest cr : mExistingClientRequests) {
                     if (cr.getPackageName().equals(callingPackage)) {
                         AmbientContextManagerPerUserService service =