[Bugfix] avoid deadlock caused by AppBatteryTracker.dump

AppBatteryTracker.dump -> BaseAppStatePolicy.shouldExemptUid -> getBackgroundRestrictionExemptionReason -> getPotentialSystemExemptionReason -> isProfileOwner
Getting mlock first in AppBatteryTracker.dump() and then getting AMS lock in isProfileOwner() is an inappropriate lock order in the above call chain. This is inconsistent with the method of getting AMS lock first and then mlock lock in most method calls, so it will cause deadlock and cause watchdog.

Similar bug cases include 366150181, 358274041

Bug:366150181
Test: Manual test

Change-Id: I8a1b509a1e95ad8570f3d4c248f9e0ed346962ad
Signed-off-by: panhaihui <panhaihui@xiaomi.com>

1 files changed, 15 insertions, 10 deletions

diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 995c17635a0a..e0db1f6e1f51 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -749,12 +749,14 @@ public class ActivityManagerService extends IActivityManager.Stub
     /**
      * Map userId to its companion app uids.
      */
+    @GuardedBy("mCompanionAppUidsMap")
     private final Map<Integer, Set<Integer>> mCompanionAppUidsMap = new ArrayMap<>();
 
     /**
      * The profile owner UIDs.
      */
-    private ArraySet<Integer> mProfileOwnerUids = null;
+    @GuardedBy("mProfileOwnerUids")
+    private final ArraySet<Integer> mProfileOwnerUids = new ArraySet<>();
 
     final UserController mUserController;
     @VisibleForTesting
@@ -19604,32 +19606,35 @@ public class ActivityManagerService extends IActivityManager.Stub
 
         @Override
         public void setProfileOwnerUid(ArraySet<Integer> profileOwnerUids) {
-            synchronized (ActivityManagerService.this) {
-                mProfileOwnerUids = profileOwnerUids;
+            synchronized (mProfileOwnerUids) {
+                mProfileOwnerUids.clear();
+                mProfileOwnerUids.addAll(profileOwnerUids);
             }
         }
 
         @Override
         public boolean isProfileOwner(int uid) {
-            synchronized (ActivityManagerService.this) {
-                return mProfileOwnerUids != null && mProfileOwnerUids.indexOf(uid) >= 0;
+            synchronized (mProfileOwnerUids) {
+                return mProfileOwnerUids.indexOf(uid) >= 0;
             }
         }
 
         @Override
         public void setCompanionAppUids(int userId, Set<Integer> companionAppUids) {
-            synchronized (ActivityManagerService.this) {
+            synchronized (mCompanionAppUidsMap) {
                 mCompanionAppUidsMap.put(userId, companionAppUids);
             }
         }
 
         @Override
         public boolean isAssociatedCompanionApp(int userId, int uid) {
-            final Set<Integer> allUids = mCompanionAppUidsMap.get(userId);
-            if (allUids == null) {
-                return false;
+            synchronized (mCompanionAppUidsMap) {
+                final Set<Integer> allUids = mCompanionAppUidsMap.get(userId);
+                if (allUids == null) {
+                    return false;
+                }
+                return allUids.contains(uid);
             }
-            return allUids.contains(uid);
         }
 
         @Override