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Commit 042e43a7 authored by Alex Salo's avatar Alex Salo
Browse files

Don't call ActivityManagerService on main thread 

AttentionManagerService is getting called from PMS with its mLock held.
PowerManagerService can't up-call to the system, thus AMS can't call
into ActivityManagerService via bindService() - put it on another
thread.

Bug: 133077390
Test: manually
Change-Id: I373163c188bc8dbbd3d4f708073a875a57cfed73
parent 2fb4cb55

services/core/java/com/android/server/attention/AttentionManagerService.java

+32 −27
Original line number Diff line number Diff line
@@ -190,9 +190,7 @@ public class AttentionManagerService extends SystemService { 


            final UserState userState = getOrCreateCurrentUserStateLocked();

            // lazily start the service, which should be very lightweight to start

            if (!userState.bindLocked()) {

                return false;

            }

            userState.bindLocked();



            // throttle frequent requests

            final AttentionCheckCache cache = userState.mAttentionCheckCache;
@@ -310,7 +308,7 @@ public class AttentionManagerService extends SystemService { 
    protected UserState getOrCreateUserStateLocked(int userId) {

        UserState result = mUserStates.get(userId);

        if (result == null) {

            result = new UserState(userId, mContext, mLock, mComponentName);

            result = new UserState(userId, mContext, mLock, mAttentionHandler, mComponentName);

            mUserStates.put(userId, result);

        }

        return result;
@@ -456,31 +454,33 @@ public class AttentionManagerService extends SystemService { 


    @VisibleForTesting

    protected static class UserState {

        final ComponentName mComponentName;

        final AttentionServiceConnection mConnection = new AttentionServiceConnection();

        private final ComponentName mComponentName;

        private final AttentionServiceConnection mConnection = new AttentionServiceConnection();



        @GuardedBy("mLock")

        IAttentionService mService;

        @GuardedBy("mLock")

        boolean mBinding;

        @GuardedBy("mLock")

        AttentionCheck mCurrentAttentionCheck;

        @GuardedBy("mLock")

        AttentionCheckCache mAttentionCheckCache;

        @GuardedBy("mLock")

        private boolean mBinding;



        @UserIdInt

        final int mUserId;

        final Context mContext;

        final Object mLock;

        private final int mUserId;

        private final Context mContext;

        private final Object mLock;

        private final Handler mAttentionHandler;



        UserState(int userId, Context context, Object lock, ComponentName componentName) {

        UserState(int userId, Context context, Object lock, Handler handler,

                ComponentName componentName) {

            mUserId = userId;

            mContext = Preconditions.checkNotNull(context);

            mLock = Preconditions.checkNotNull(lock);

            mComponentName = Preconditions.checkNotNull(componentName);

            mAttentionHandler = handler;

        }





        @GuardedBy("mLock")

        private void handlePendingCallbackLocked() {

            if (!mCurrentAttentionCheck.mIsDispatched) {
@@ -499,26 +499,25 @@ public class AttentionManagerService extends SystemService { 


        /** Binds to the system's AttentionService which provides an actual implementation. */

        @GuardedBy("mLock")

        private boolean bindLocked() {

        private void bindLocked() {

            // No need to bind if service is binding or has already been bound.

            if (mBinding || mService != null) {

                return true;

                return;

            }



            final boolean willBind;

            final long identity = Binder.clearCallingIdentity();



            try {

                final Intent mServiceIntent = new Intent(

            mBinding = true;

            // mContext.bindServiceAsUser() calls into ActivityManagerService which it may already

            // hold the lock and had called into PowerManagerService, which holds a lock.

            // That would create a deadlock. To solve that, putting it on a handler.

            mAttentionHandler.post(() -> {

                final Intent serviceIntent = new Intent(

                        AttentionService.SERVICE_INTERFACE).setComponent(

                        mComponentName);

                willBind = mContext.bindServiceAsUser(mServiceIntent, mConnection,

                // Note: no reason to clear the calling identity, we won't have one in a handler.

                mContext.bindServiceAsUser(serviceIntent, mConnection,

                        Context.BIND_AUTO_CREATE, UserHandle.CURRENT);

                mBinding = willBind;

            } finally {

                Binder.restoreCallingIdentity(identity);

            }

            return willBind;



            });

        }



        private void dump(IndentingPrintWriter pw) {
@@ -587,6 +586,7 @@ public class AttentionManagerService extends SystemService { 
            super(Looper.myLooper());

        }



        @Override

        public void handleMessage(Message msg) {

            switch (msg.what) {

                // Do not occupy resources when not in use - unbind proactively.
@@ -651,7 +651,12 @@ public class AttentionManagerService extends SystemService { 
                return;

            }



            mContext.unbindService(userState.mConnection);

            mAttentionHandler.post(() -> mContext.unbindService(userState.mConnection));

            // Note: this will set mBinding to false even though it could still be trying to bind

            // (i.e. the runnable was posted in bindLocked but then cancelAndUnbindLocked was

            // called before it's run yet). This is a safe state at the moment,

            // since it will eventually, but feels like a source for confusion down the road and

            // may cause some expensive and unnecessary work to be done.

            userState.mConnection.cleanupService();

            mUserStates.remove(userState.mUserId);

        }

services/tests/servicestests/src/com/android/server/attention/AttentionManagerServiceTest.java

+1 −0
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ public class AttentionManagerServiceTest { 
        UserState mUserState = new UserState(0,

                mContext,

                mLock,

                mMockHandler,

                componentName);

        mUserState.mService = new MockIAttentionService();

        mSpyUserState = spy(mUserState);