From 0c54aa175ed52c6c30a758bb527987513a308893 Mon Sep 17 00:00:00 2001
From: Yasin Kilicdere <tyk@google.com>
Date: Thu, 11 Aug 2022 15:50:29 +0100
Subject: [PATCH] Unregister user switch observer in
 ActivityManagerShellCommand.

ActivityManagerShellCommand does not unregisterUserSwitchObserver
after registerUserSwitchObserver, which leads to a leak of
unnecessary callbacks. This CL adds unregistering in finally block.

Bug: 242176088
Test: Manual test with adb and perfetto.
Change-Id: I14d66a00c5dd3f881d393a386a2678835c99a900
---
 .../am/ActivityManagerShellCommand.java       | 52 +++++++++++--------
 1 file changed, 29 insertions(+), 23 deletions(-)

diff --git a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
index 6609d4a91f21a..55471410cfd2c 100644
--- a/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
+++ b/services/core/java/com/android/server/am/ActivityManagerShellCommand.java
@@ -51,6 +51,7 @@ import android.app.IActivityManager;
 import android.app.IActivityTaskManager;
 import android.app.IStopUserCallback;
 import android.app.IUidObserver;
+import android.app.IUserSwitchObserver;
 import android.app.KeyguardManager;
 import android.app.ProfilerInfo;
 import android.app.RemoteServiceException.CrashedByAdbException;
@@ -1937,31 +1938,36 @@ final class ActivityManagerShellCommand extends ShellCommand {
 
         // Register switch observer.
         final CountDownLatch switchLatch = new CountDownLatch(1);
-        mInterface.registerUserSwitchObserver(
-                new UserSwitchObserver() {
-                    @Override
-                    public void onUserSwitchComplete(int newUserId) {
-                        if (userId == newUserId) {
-                            switchLatch.countDown();
-                        }
-                    }
-                }, ActivityManagerShellCommand.class.getName());
-
-        // Switch.
-        boolean switched = mInterface.switchUser(userId);
-        if (!switched) {
-            // Switching failed, don't wait for the user switch observer.
-            return false;
-        }
-
-        // Wait.
+        final IUserSwitchObserver userSwitchObserver = new UserSwitchObserver() {
+            @Override
+            public void onUserSwitchComplete(int newUserId) {
+                if (userId == newUserId) {
+                    switchLatch.countDown();
+                }
+            }
+        };
         try {
-            switched = switchLatch.await(USER_OPERATION_TIMEOUT_MS, TimeUnit.MILLISECONDS);
-        } catch (InterruptedException e) {
-            getErrPrintWriter().println("Error: Thread interrupted unexpectedly.");
-        }
+            mInterface.registerUserSwitchObserver(userSwitchObserver,
+                    ActivityManagerShellCommand.class.getName());
 
-        return switched;
+            // Switch.
+            boolean switched = mInterface.switchUser(userId);
+            if (!switched) {
+                // Switching failed, don't wait for the user switch observer.
+                return false;
+            }
+
+            // Wait.
+            try {
+                switched = switchLatch.await(USER_OPERATION_TIMEOUT_MS, TimeUnit.MILLISECONDS);
+            } catch (InterruptedException e) {
+                getErrPrintWriter().println("Error: Thread interrupted unexpectedly.");
+            }
+
+            return switched;
+        } finally {
+            mInterface.unregisterUserSwitchObserver(userSwitchObserver);
+        }
     }
 
     int runSwitchUser(PrintWriter pw) throws RemoteException {