diff --git a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
index f4d76c2603a2b..a50c4a1b85c00 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskManagerService.java
@@ -6363,7 +6363,7 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
                 int wakefulness) {
             synchronized (mGlobalLock) {
                 if (mHomeProcess != null && (dumpPackage == null
-                        || mHomeProcess.mPkgList.contains(dumpPackage))) {
+                        || mHomeProcess.containsPackage(dumpPackage))) {
                     if (needSep) {
                         pw.println();
                         needSep = false;
@@ -6371,7 +6371,7 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
                     pw.println("  mHomeProcess: " + mHomeProcess);
                 }
                 if (mPreviousProcess != null && (dumpPackage == null
-                        || mPreviousProcess.mPkgList.contains(dumpPackage))) {
+                        || mPreviousProcess.containsPackage(dumpPackage))) {
                     if (needSep) {
                         pw.println();
                         needSep = false;
@@ -6379,14 +6379,14 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
                     pw.println("  mPreviousProcess: " + mPreviousProcess);
                 }
                 if (dumpAll && (mPreviousProcess == null || dumpPackage == null
-                        || mPreviousProcess.mPkgList.contains(dumpPackage))) {
+                        || mPreviousProcess.containsPackage(dumpPackage))) {
                     StringBuilder sb = new StringBuilder(128);
                     sb.append("  mPreviousProcessVisibleTime: ");
                     TimeUtils.formatDuration(mPreviousProcessVisibleTime, sb);
                     pw.println(sb);
                 }
                 if (mHeavyWeightProcess != null && (dumpPackage == null
-                        || mHeavyWeightProcess.mPkgList.contains(dumpPackage))) {
+                        || mHeavyWeightProcess.containsPackage(dumpPackage))) {
                     if (needSep) {
                         pw.println();
                         needSep = false;
@@ -6510,18 +6510,18 @@ public class ActivityTaskManagerService extends IActivityTaskManager.Stub {
                 }
 
                 if (mHomeProcess != null && (dumpPackage == null
-                        || mHomeProcess.mPkgList.contains(dumpPackage))) {
+                        || mHomeProcess.containsPackage(dumpPackage))) {
                     mHomeProcess.dumpDebug(proto, HOME_PROC);
                 }
 
                 if (mPreviousProcess != null && (dumpPackage == null
-                        || mPreviousProcess.mPkgList.contains(dumpPackage))) {
+                        || mPreviousProcess.containsPackage(dumpPackage))) {
                     mPreviousProcess.dumpDebug(proto, PREVIOUS_PROC);
                     proto.write(PREVIOUS_PROC_VISIBLE_TIME_MS, mPreviousProcessVisibleTime);
                 }
 
                 if (mHeavyWeightProcess != null && (dumpPackage == null
-                        || mHeavyWeightProcess.mPkgList.contains(dumpPackage))) {
+                        || mHeavyWeightProcess.containsPackage(dumpPackage))) {
                     mHeavyWeightProcess.dumpDebug(proto, HEAVY_WEIGHT_PROC);
                 }
 
diff --git a/services/core/java/com/android/server/wm/ActivityTaskSupervisor.java b/services/core/java/com/android/server/wm/ActivityTaskSupervisor.java
index 3f885f3ab23f5..8184bd63bffee 100644
--- a/services/core/java/com/android/server/wm/ActivityTaskSupervisor.java
+++ b/services/core/java/com/android/server/wm/ActivityTaskSupervisor.java
@@ -1717,7 +1717,7 @@ public class ActivityTaskSupervisor implements RecentTasks.Callbacks {
                     // Don't kill the home process along with tasks from the same package.
                     continue;
                 }
-                if (!proc.mPkgList.contains(pkg)) {
+                if (!proc.containsPackage(pkg)) {
                     // Don't kill process that is not associated with this task.
                     continue;
                 }
diff --git a/services/core/java/com/android/server/wm/CompatModePackages.java b/services/core/java/com/android/server/wm/CompatModePackages.java
index a035948564dc2..d5828ef082512 100644
--- a/services/core/java/com/android/server/wm/CompatModePackages.java
+++ b/services/core/java/com/android/server/wm/CompatModePackages.java
@@ -566,7 +566,7 @@ public final class CompatModePackages {
             SparseArray<WindowProcessController> pidMap = mService.mProcessMap.getPidMap();
             for (int i = pidMap.size() - 1; i >= 0; i--) {
                 final WindowProcessController app = pidMap.valueAt(i);
-                if (!app.mPkgList.contains(packageName)) {
+                if (!app.containsPackage(packageName)) {
                     continue;
                 }
                 try {
diff --git a/services/core/java/com/android/server/wm/WindowProcessController.java b/services/core/java/com/android/server/wm/WindowProcessController.java
index 91452c6663a26..eb5d7a8583bd1 100644
--- a/services/core/java/com/android/server/wm/WindowProcessController.java
+++ b/services/core/java/com/android/server/wm/WindowProcessController.java
@@ -73,6 +73,7 @@ import android.util.Slog;
 import android.util.proto.ProtoOutputStream;
 import android.view.IRemoteAnimationRunner;
 
+import com.android.internal.annotations.GuardedBy;
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.app.HeavyWeightSwitcherActivity;
 import com.android.internal.protolog.common.ProtoLog;
@@ -115,7 +116,8 @@ public class WindowProcessController extends ConfigurationContainer<Configuratio
     // communicate back to the activity manager side.
     public final Object mOwner;
     // List of packages running in the process
-    final ArraySet<String> mPkgList = new ArraySet<>();
+    @GuardedBy("itself")
+    private final ArrayList<String> mPkgList = new ArrayList<>(1);
     private final WindowProcessListener mListener;
     private final ActivityTaskManagerService mAtm;
     private final BackgroundLaunchProcessController mBgLaunchController;
@@ -640,18 +642,26 @@ public class WindowProcessController extends ConfigurationContainer<Configuratio
 
     @HotPath(caller = HotPath.PROCESS_CHANGE)
     public void addPackage(String packageName) {
-        synchronized (mAtm.mGlobalLockWithoutBoost) {
-            mPkgList.add(packageName);
+        synchronized (mPkgList) {
+            if (!mPkgList.contains(packageName)) {
+                mPkgList.add(packageName);
+            }
         }
     }
 
     @HotPath(caller = HotPath.PROCESS_CHANGE)
     public void clearPackageList() {
-        synchronized (mAtm.mGlobalLockWithoutBoost) {
+        synchronized (mPkgList) {
             mPkgList.clear();
         }
     }
 
+    boolean containsPackage(String packageName) {
+        synchronized (mPkgList) {
+            return mPkgList.contains(packageName);
+        }
+    }
+
     void addActivityIfNeeded(ActivityRecord r) {
         // even if we already track this activity, note down that it has been launched
         setLastActivityLaunchTime(r.lastLaunchTime);