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Commit 123aa680 authored by Lakshman Annadorai's avatar Lakshman Annadorai
Browse files

Skip duplicate USER_SYSTEM start in SystemServiceManager. 

On Automotive / Headless System User Mode, the system user will be
started twice - once from ActivityServiceManager and once from an
external/local service that switches the system user to background in
HSUM.

Previously, checking for the current user on the ActivityServiceManager
side helped avoid starting system user twice because
the CarServiceHelperService, which resides in the same process, started
the system user before ActivityServiceManager and switched the user to
the background.
But this doesn't work anymore because the order of these calls are
non-deteministic. The system user start is moved to CarService, which
resides in a separate process (which increases the chances of
the non-deterministic event).

Avoid starting system user twice by explicitly checking against the list
of previously started users on the SystemServiceManager side.
On the ActivityServiceManager side, protect against starting home
displays, and broadcasting system user start/switch on HSUM by
explicitly checking for HSUM.

Test: Build and system boot up is okay.
Test: Ran `adb shell dumpsys system_server_dumper --name \
           SystemServiceManager | grep user`
      and verified the running user(s) is listed.
Bug: 258532055
Change-Id: Ic0af6b030c08995715dd3195801ed271c690ce4a
parent 2c4de386

services/core/java/com/android/server/SystemServiceManager.java

+14 −2
Original line number Diff line number Diff line
@@ -351,12 +351,24 @@ public final class SystemServiceManager implements Dumpable { 
     * Starts the given user.

     */

    public void onUserStarting(@NonNull TimingsTraceAndSlog t, @UserIdInt int userId) {

        EventLog.writeEvent(EventLogTags.SSM_USER_STARTING, userId);



        final TargetUser targetUser = newTargetUser(userId);

        synchronized (mTargetUsers) {

            // On Automotive / Headless System User Mode, the system user will be started twice:

            // - Once by some external or local service that switches the system user to

            //   the background.

            // - Once by the ActivityManagerService, when the system is marked ready.

            // These two events are not synchronized and the order of execution is

            // non-deterministic. To avoid starting the system user twice, verify whether

            // the system user has already been started by checking the mTargetUsers.

            // TODO(b/242195409): this workaround shouldn't be necessary once we move

            // the headless-user start logic to UserManager-land.

            if (userId == UserHandle.USER_SYSTEM && mTargetUsers.contains(userId)) {

                Slog.e(TAG, "Skipping starting system user twice");

                return;

            }

            mTargetUsers.put(userId, targetUser);

        }

        EventLog.writeEvent(EventLogTags.SSM_USER_STARTING, userId);

        onUser(t, USER_STARTING, /* prevUser= */ null, targetUser);

    }

services/core/java/com/android/server/am/ActivityManagerService.java

+14 −9
Original line number Diff line number Diff line
@@ -8402,13 +8402,10 @@ public class ActivityManagerService extends IActivityManager.Stub 














        // On Automotive / Headless System User Mode, at this point the system user has already been















        // started and unlocked, and some of the tasks we do here have already been done. So skip













        // those in that case.













        // those in that case. The duplicate system user start is guarded in SystemServiceManager.















        // TODO(b/242195409): this workaround shouldn't be necessary once we move the headless-user













        // start logic to UserManager-land













        final boolean bootingSystemUser = currentUserId == UserHandle.USER_SYSTEM;













        if (bootingSystemUser) {













        // start logic to UserManager-land.















        mUserController.onSystemUserStarting();













        }





























        synchronized (this) {















            // Only start up encryption-aware persistent apps; once user is










@@ -8438,7 +8435,15 @@ public class ActivityManagerService extends IActivityManager.Stub













                t.traceEnd();















            }



























            if (bootingSystemUser) {













            // Some systems - like automotive - will explicitly unlock system user then switch













            // to a secondary user. Hence, we don't want to send duplicate broadcasts for













            // the system user here.













            // TODO(b/242195409): this workaround shouldn't be necessary once we move













            // the headless-user start logic to UserManager-land.













            final boolean isBootingSystemUser = (currentUserId == UserHandle.USER_SYSTEM)













                    && !UserManager.isHeadlessSystemUserMode();

























            if (isBootingSystemUser) {















                t.traceBegin("startHomeOnAllDisplays");















                mAtmInternal.startHomeOnAllDisplays(currentUserId, "systemReady");















                t.traceEnd();









@@ -8449,7 +8454,7 @@ public class ActivityManagerService extends IActivityManager.Stub













            t.traceEnd();









































            if (bootingSystemUser) {













            if (isBootingSystemUser) {















                t.traceBegin("sendUserStartBroadcast");















                final int callingUid = Binder.getCallingUid();















                final int callingPid = Binder.getCallingPid();










@@ -8490,7 +8495,7 @@ public class ActivityManagerService extends IActivityManager.Stub













            mAtmInternal.resumeTopActivities(false /* scheduleIdle */);















            t.traceEnd();



























            if (bootingSystemUser) {













            if (isBootingSystemUser) {















                t.traceBegin("sendUserSwitchBroadcasts");















                mUserController.sendUserSwitchBroadcasts(-1, currentUserId);















                t.traceEnd();