From 6b9ec6e616d5401e300152b379aef6ab52220b87 Mon Sep 17 00:00:00 2001
From: Kweku Adams <kwekua@google.com>
Date: Fri, 24 Feb 2023 01:59:28 +0000
Subject: [PATCH] Fix NPE.

Avoid an NPE in the shell command handler when ActivityManagerService
doesn't have a top app record.

Bug: 261999509
Test: atest FrameworksServicesTests:ActivityManagerServiceTest
Change-Id: I0bcc45873a4672c59769dbc67b164bb9bbece8cd
---
 .../com/android/server/am/ActivityManagerService.java |  1 +
 .../server/am/ActivityManagerShellCommand.java        | 11 ++++++++---
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 6aa49d276391d..cd29d52ebaed4 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -16325,6 +16325,7 @@ public class ActivityManagerService extends IActivityManager.Stub
 
     // TODO(b/111541062): This method is only used for updating OOM adjustments. We need to update
     // the logic there and in mBatteryStatsService to make them aware of multiple resumed activities
+    @Nullable
     ProcessRecord getTopApp() {
         final WindowProcessController wpc = mAtmInternal != null ? mAtmInternal.getTopApp() : null;
         final ProcessRecord r = wpc != null ? (ProcessRecord) wpc.mOwner : null;
diff --git a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
index aa9d4ccc61abb..72d6ca9fd7619 100644
--- a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
+++ b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
@@ -3531,9 +3531,14 @@ final class ActivityManagerShellCommand extends ShellCommand {
             if (foregroundActivities) {
                 try {
                     int prcState = mIam.getUidProcessState(uid, "android");
-                    int topPid = mInternal.getTopApp().getPid();
-                    if (prcState == ProcessStateEnum.TOP && topPid == pid) {
-                        mPw.println("New foreground process: " + pid);
+                    ProcessRecord topApp = mInternal.getTopApp();
+                    if (topApp == null) {
+                        mPw.println("No top app found");
+                    } else {
+                        int topPid = topApp.getPid();
+                        if (prcState == ProcessStateEnum.TOP && topPid == pid) {
+                            mPw.println("New foreground process: " + pid);
+                        }
                     }
                     mPw.flush();
                 } catch (RemoteException e) {