Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 0bf3dc98 authored by Seigo Nonaka's avatar Seigo Nonaka
Browse files

Fix race condition of removing surface. 

mContainer.startingSurface can be replaced between posting
mRemoveStartingWindow and actually surface.remove() is called.

1. removeStartingWindow is called, then mRemoveStartingWindow is posted
   to mHandler
2. transferStartingWindow is called, then mContainer.startingWindow is
   replaced with new surface.
3. mHandler pops the callback and surface.remove() is called.

Here the remove is only called for replaced surface and never called for
older surface.

To fix this issue, surely removes the surface when the
removeStartingWindow is called.

Bug: 63156080
Bug: 63784898
Test: Watch /proc/<pid>/fd
Change-Id: Iccf13bdc98b4012168910305568f5dd4bbedbf54
Merged-In: I55e2c1b8fba32b3a19603e6ad4743f07576abd48
parent 8e644a75

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

+29 −44
Original line number Diff line number Diff line
@@ -115,41 +115,6 @@ public class AppWindowContainerController 
        mListener.onWindowsGone();

    };



    private final Runnable mRemoveStartingWindow = () -> {

        StartingSurface surface = null;

        synchronized (mWindowMap) {

            if (mContainer == null) {

                if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "mContainer was null while trying to"

                        + " remove starting window");

                return;

            }

            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Remove starting " + mContainer

                    + ": startingWindow=" + mContainer.startingWindow

                    + " startingView=" + mContainer.startingSurface);

            if (mContainer.startingData != null) {

                surface = mContainer.startingSurface;

                mContainer.startingData = null;

                mContainer.startingSurface = null;

                mContainer.startingWindow = null;

                mContainer.startingDisplayed = false;

                if (surface == null && DEBUG_STARTING_WINDOW) {

                    Slog.v(TAG_WM, "startingWindow was set but startingSurface==null, couldn't "

                            + "remove");

                }

            } else if (DEBUG_STARTING_WINDOW) {

                Slog.v(TAG_WM, "Tried to remove starting window but startingWindow was null:"

                        + mContainer);

            }

        }

        if (surface != null) {

            try {

                surface.remove();

            } catch (Exception e) {

                Slog.w(TAG_WM, "Exception when removing starting window", e);

            }

        }

    };



    private final Runnable mAddStartingWindow = () -> {

        final StartingData startingData;

        final AppWindowToken container;
@@ -649,13 +614,6 @@ public class AppWindowContainerController 


    public void removeStartingWindow() {

        synchronized (mWindowMap) {

            if (mHandler.hasCallbacks(mRemoveStartingWindow)) {

                // Already scheduled.

                if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Trying to remove starting window but "

                        + "already scheduled");

                return;

            }



            if (mContainer.startingWindow == null) {

                if (mContainer.startingData != null) {

                    // Starting window has not been added yet, but it is scheduled to be added.
@@ -667,9 +625,36 @@ public class AppWindowContainerController 
                return;

            }



            final StartingSurface surface;

            if (mContainer.startingData != null) {

                surface = mContainer.startingSurface;

                mContainer.startingData = null;

                mContainer.startingSurface = null;

                mContainer.startingWindow = null;

                mContainer.startingDisplayed = false;

                if (surface == null && DEBUG_STARTING_WINDOW) {

                    Slog.v(TAG_WM, "startingWindow was set but startingSurface==null, couldn't "

                            + "remove");

                }

            } else {

                if (DEBUG_STARTING_WINDOW) {

                    Slog.v(TAG_WM, "Tried to remove starting window but startingWindow was null:"

                            + mContainer);

                }

                return;

            }



            if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Schedule remove starting " + mContainer

                    + " startingWindow=" + mContainer.startingWindow);

            mHandler.post(mRemoveStartingWindow);

                    + " startingWindow=" + mContainer.startingWindow

                    + " startingView=" + mContainer.startingSurface);

            mHandler.post(() -> {

                if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Removing startingView=" + surface);

                try {

                    surface.remove();

                } catch (Exception e) {

                    Slog.w(TAG_WM, "Exception when removing starting window", e);

                }

            });

        }

    }