Fix WM missing stack/task when activity is force stopped and restarted
When activity process is force-stopped (like in the case we need to stop
it to allow debugger), activity record is removed and a new instance is
added. Depending on timing, adding of new record could happen before
or after old record is removed. If it added after old record is removed,
then the removal could cause AM to also remove the task AND the stack
(if the activity is the last one).
On WM side however, the task/stack removal could be delayed due to
animation. So when AM attaches a new stack, we end up with two stacks
with the same stack id in the DisplayContent. Also, AM reuses the last
used taskId after it's deleted. So WM is confused and didn't add a new
task record. Then when the delayed stack removal fires everything is gone.
We need to use a different task id when creating a new task record, even
if the last created task is already deleted. Also when attaching a new
stack to WM, first check if we already have such a stack in DisplayContent,
if so, reattach it and don't create a duplicate.
bug: 30465601
Change-Id: Ic399a32c54f6acdcbb9a0c6155599331d55df232
diff --git a/services/core/java/com/android/server/am/ActivityStackSupervisor.java b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
index e31df57..ece1ee9 100644
--- a/services/core/java/com/android/server/am/ActivityStackSupervisor.java
+++ b/services/core/java/com/android/server/am/ActivityStackSupervisor.java
@@ -781,20 +781,25 @@
}
}
+ static int nextTaskIdForUser(int taskId, int userId) {
+ int nextTaskId = taskId + 1;
+ if (nextTaskId == (userId + 1) * MAX_TASK_IDS_PER_USER) {
+ // Wrap around as there will be smaller task ids that are available now.
+ nextTaskId -= MAX_TASK_IDS_PER_USER;
+ }
+ return nextTaskId;
+ }
+
int getNextTaskIdForUserLocked(int userId) {
final int currentTaskId = mCurTaskIdForUser.get(userId, userId * MAX_TASK_IDS_PER_USER);
// for a userId u, a taskId can only be in the range
// [u*MAX_TASK_IDS_PER_USER, (u+1)*MAX_TASK_IDS_PER_USER-1], so if MAX_TASK_IDS_PER_USER
// was 10, user 0 could only have taskIds 0 to 9, user 1: 10 to 19, user 2: 20 to 29, so on.
- int candidateTaskId = currentTaskId;
+ int candidateTaskId = nextTaskIdForUser(currentTaskId, userId);
while (mRecentTasks.taskIdTakenForUserLocked(candidateTaskId, userId)
|| anyTaskForIdLocked(candidateTaskId, !RESTORE_FROM_RECENTS,
INVALID_STACK_ID) != null) {
- candidateTaskId++;
- if (candidateTaskId == (userId + 1) * MAX_TASK_IDS_PER_USER) {
- // Wrap around as there will be smaller task ids that are available now.
- candidateTaskId -= MAX_TASK_IDS_PER_USER;
- }
+ candidateTaskId = nextTaskIdForUser(candidateTaskId, userId);
if (candidateTaskId == currentTaskId) {
// Something wrong!
// All MAX_TASK_IDS_PER_USER task ids are taken up by running tasks for this user
diff --git a/services/core/java/com/android/server/wm/DisplayContent.java b/services/core/java/com/android/server/wm/DisplayContent.java
index fba439f..1d57872 100644
--- a/services/core/java/com/android/server/wm/DisplayContent.java
+++ b/services/core/java/com/android/server/wm/DisplayContent.java
@@ -191,6 +191,16 @@
return mHomeStack;
}
+ TaskStack getStackById(int stackId) {
+ for (int i = mStacks.size() - 1; i >= 0; --i) {
+ final TaskStack stack = mStacks.get(i);
+ if (stack.mStackId == stackId) {
+ return stack;
+ }
+ }
+ return null;
+ }
+
void updateDisplayInfo() {
mDisplay.getDisplayInfo(mDisplayInfo);
mDisplay.getMetrics(mDisplayMetrics);
diff --git a/services/core/java/com/android/server/wm/WindowManagerService.java b/services/core/java/com/android/server/wm/WindowManagerService.java
index 6451c74..6a184b2 100644
--- a/services/core/java/com/android/server/wm/WindowManagerService.java
+++ b/services/core/java/com/android/server/wm/WindowManagerService.java
@@ -5047,18 +5047,32 @@
try {
synchronized (mWindowMap) {
final DisplayContent displayContent = mDisplayContents.get(displayId);
+ boolean attachedToDisplay = false;
if (displayContent != null) {
TaskStack stack = mStackIdToStack.get(stackId);
if (stack == null) {
if (DEBUG_STACK) Slog.d(TAG_WM, "attachStack: stackId=" + stackId);
- stack = new TaskStack(this, stackId);
+
+ stack = displayContent.getStackById(stackId);
+ if (stack != null) {
+ // It's already attached to the display. Detach and re-attach
+ // because onTop might change, and be sure to clear mDeferDetach!
+ displayContent.detachStack(stack);
+ stack.mDeferDetach = false;
+ attachedToDisplay = true;
+ } else {
+ stack = new TaskStack(this, stackId);
+ }
+
mStackIdToStack.put(stackId, stack);
if (stackId == DOCKED_STACK_ID) {
getDefaultDisplayContentLocked().mDividerControllerLocked
.notifyDockedStackExistsChanged(true);
}
}
- stack.attachDisplayContent(displayContent);
+ if (!attachedToDisplay) {
+ stack.attachDisplayContent(displayContent);
+ }
displayContent.attachStack(stack, onTop);
if (stack.getRawFullscreen()) {
return null;
