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Commit a2363540 authored by nttsai's avatar nttsai Committed by NT Tsai
Browse files

Fix a deadlock WMG->WMS, WMS->WMG 

In ImmersiveModeConfirmation, the WindowManager operations shouldn't be
called while holding the WM lock. Thus, I remove the assigned operation of
mWindowManager member in the constructor function. Next, I add a private
function to get a valid mWindowManager member in 3 functions (handleHide,
handleShow, onAttachedToWindow). The 3 functions are called by a different
thread by specific events. It should avoid the deadlock we saw now.

Bug: 129101307, 128520392
Test: local build and manually test it for 2 times
Test Steps: 1. Boot up the device 2. Start Photo to view a photo in full
screen and exit full screen
Change-Id: If42f4fd6a31869d5eefa8b445c32665aef1ee07d
parent a498804d

services/core/java/com/android/server/wm/ImmersiveModeConfirmation.java

+16 −5
Original line number Diff line number Diff line
@@ -90,8 +90,6 @@ public class ImmersiveModeConfirmation { 
        mShowDelayMs = getNavBarExitDuration() * 3;

        mPanicThresholdMs = context.getResources()

                .getInteger(R.integer.config_immersive_mode_confirmation_panic);

        mWindowManager = (WindowManager)

                mContext.getSystemService(Context.WINDOW_SERVICE);

        mVrModeEnabled = vrModeEnabled;

    }
@@ -177,7 +175,7 @@ public class ImmersiveModeConfirmation { 
    private void handleHide() {

        if (mClingWindow != null) {

            if (DEBUG) Slog.d(TAG, "Hiding immersive mode confirmation");

            mWindowManager.removeView(mClingWindow);

            getWindowManager().removeView(mClingWindow);

            mClingWindow = null;

        }

    }
@@ -275,7 +273,7 @@ public class ImmersiveModeConfirmation { 
            super.onAttachedToWindow();



            DisplayMetrics metrics = new DisplayMetrics();

            mWindowManager.getDefaultDisplay().getMetrics(metrics);

            getWindowManager().getDefaultDisplay().getMetrics(metrics);

            float density = metrics.density;



            getViewTreeObserver().addOnComputeInternalInsetsListener(mInsetsListener);
@@ -341,6 +339,19 @@ public class ImmersiveModeConfirmation { 
        }

    }



    /**

     * DO HOLD THE WINDOW MANAGER LOCK WHEN CALLING THIS METHOD

     * The reason why we add this method is to avoid the deadlock of WMG->WMS and WMS->WMG

     * when ImmersiveModeConfirmation object is created.

     */

    private WindowManager getWindowManager() {

        if (mWindowManager == null) {

            mWindowManager = (WindowManager)

                      mContext.getSystemService(Context.WINDOW_SERVICE);

        }

        return mWindowManager;

    }



    private void handleShow() {

        if (DEBUG) Slog.d(TAG, "Showing immersive mode confirmation");
@@ -352,7 +363,7 @@ public class ImmersiveModeConfirmation { 


        // show the confirmation

        WindowManager.LayoutParams lp = getClingWindowLayoutParams();

        mWindowManager.addView(mClingWindow, lp);

        getWindowManager().addView(mClingWindow, lp);

    }



    private final Runnable mConfirm = new Runnable() {