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Fix starting window leak when adding/removing quickly

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The following race condition may happen when transferring starting
windows:
- Add thread (android.anim) calls Snapshot.create
- Remove thread (android.display!) checks that yes there is a
starting window, but no surface yet. Thus, it nulls out everything.
- Add thread returns from Snapshot.create: container.startingData
is null but startingWindow is also null. Thus, we never set
abort=true and we never set the starting window properly or remove
it properly.

Test: Some basic starting window sanity testing. Otherwise, pray
to the race condition gods.
Test: AppWindowContainerControllerTests#testAddRemoveRace
Fixes: 37888853

Change-Id: Ia287bfa52f708b36ff93ef7cd45a0d080bd4dd9c
This commit is contained in:
Jorim Jaggi
2017-05-23 18:00:48 +02:00
parent 23cc9aa50a
commit cfeff74317
2 changed files with 35 additions and 12 deletions
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22
services/core/java/com/android/server/wm/AppWindowContainerController.java
View File

@@ -107,7 +107,7 @@ public class AppWindowContainerController
if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM, "Remove starting " + mContainer
+ ": startingWindow=" + mContainer.startingWindow
+ " startingView=" + mContainer.startingSurface);
if (mContainer.startingWindow != null) {
if (mContainer.startingData != null) {
surface = mContainer.startingSurface;
mContainer.startingData = null;
mContainer.startingSurface = null;
@@ -164,18 +164,16 @@ public class AppWindowContainerController
if (surface != null) {
boolean abort = false;
synchronized(mWindowMap) {
// If the window was successfully added, then
// we need to remove it.
if (container.removed || container.startingData == null) {
// If the window was successfully added, then
// we need to remove it.
if (container.startingWindow != null) {
if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM,
"Aborted starting " + container
+ ": removed=" + container.removed
+ " startingData=" + container.startingData);
container.startingWindow = null;
container.startingData = null;
abort = true;
}
if (DEBUG_STARTING_WINDOW) Slog.v(TAG_WM,
"Aborted starting " + container
+ ": removed=" + container.removed
+ " startingData=" + container.startingData);
container.startingWindow = null;
container.startingData = null;
abort = true;
} else {
container.startingSurface = surface;
}

25
services/tests/servicestests/src/com/android/server/wm/AppWindowContainerControllerTests.java
View File

@@ -19,18 +19,24 @@ package com.android.server.wm;
import org.junit.Test;
import android.platform.test.annotations.Presubmit;
import android.platform.test.annotations.SecurityTest;
import android.support.test.InstrumentationRegistry;
import android.support.test.filters.SmallTest;
import android.support.test.runner.AndroidJUnit4;
import android.view.WindowManager;
import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE;
import static android.content.pm.ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED;
import static android.content.res.Configuration.EMPTY;
import static android.view.WindowManager.LayoutParams.TYPE_APPLICATION_STARTING;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.fail;
import java.util.function.Consumer;
/**
* Test class for {@link AppWindowContainerController}.
*
@@ -90,6 +96,9 @@ public class AppWindowContainerControllerTests extends WindowTestsBase {
assertNull(atoken.startingSurface);
assertNull(atoken.startingWindow);
assertNull(atoken.startingData);
atoken.forAllWindows(windowState -> {
assertFalse(windowState.getBaseType() == TYPE_APPLICATION_STARTING);
}, true);
}
@Test
@@ -107,6 +116,22 @@ public class AppWindowContainerControllerTests extends WindowTestsBase {
assertNoStartingWindow(atoken);
}
@Test
public void testAddRemoveRace() throws Exception {
// There was once a race condition between adding and removing starting windows
for (int i = 0; i < 1000; i++) {
final WindowTestUtils.TestAppWindowContainerController controller =
createAppWindowController();
controller.addStartingWindow(InstrumentationRegistry.getContext().getPackageName(),
android.R.style.Theme, null, "Test", 0, 0, 0, 0, null, true, true, false, true,
false);
controller.removeStartingWindow();
waitUntilHandlersIdle();
assertNoStartingWindow(controller.getAppWindowToken(mDisplayContent));
}
}
@Test
public void testTransferStartingWindow() throws Exception {
final WindowTestUtils.TestAppWindowContainerController controller1 =