commit af769b1e0bf09e9a8a4a6bc45914d17cd4f6b799
author Antony Sargent <asargent@google.com> Fri Apr 08 07:00:51 2022 -0700
committer Antony Sargent <asargent@google.com> Thu May 05 00:25:15 2022 +0000
tree e3b77c8f839045a071078ffcc60e6eccc73b966f
parent e5f9c3da5c3350f4e116e5992957f8017e763854

Prevent deadlock when releasing VirtualDisplays

When releasing a VirtualDisplay owned by a VirtualDevice, the
VirtualDeviceManagerService needs to release a WakeLock it holds on
behalf of the display. This needs to happen outside of the
synchronized block in DisplayManagerService, because releasing the
WakeLock ends up calling back into the DisplayManagerService.

Fixes: 224775363
Test: atest StreamedAppBehaviorTest
Change-Id: Ie831fcad7105d51c64717c3e00d332c543de3b47

services/core/java/com/android/server/display/DisplayManagerService.java

diff --git a/services/core/java/com/android/server/display/DisplayManagerService.java b/services/core/java/com/android/server/display/DisplayManagerService.java
index 5fcdc8a..f3b2738 100644
--- a/services/core/java/com/android/server/display/DisplayManagerService.java
+++ b/services/core/java/com/android/server/display/DisplayManagerService.java
@@ -1459,16 +1459,6 @@
             DisplayDevice device =
                     mVirtualDisplayAdapter.releaseVirtualDisplayLocked(appToken);
             if (device != null) {
-                final LogicalDisplay display = mLogicalDisplayMapper.getDisplayLocked(device);
-                if (display != null) {
-                    final int displayId = display.getDisplayIdLocked();
-                    if (mDisplayWindowPolicyControllers.contains(displayId)) {
-                        Pair<IVirtualDevice, DisplayWindowPolicyController> pair =
-                                mDisplayWindowPolicyControllers.removeReturnOld(displayId);
-                        getLocalService(VirtualDeviceManagerInternal.class)
-                                .onVirtualDisplayRemoved(pair.first, displayId);
-                    }
-                }
                 // TODO: multi-display - handle virtual displays the same as other display adapters.
                 mDisplayDeviceRepo.onDisplayDeviceEvent(device,
                         DisplayAdapter.DISPLAY_DEVICE_EVENT_REMOVED);
@@ -1628,6 +1618,17 @@
         DisplayManagerGlobal.invalidateLocalDisplayInfoCaches();
         sendDisplayEventLocked(displayId, DisplayManagerGlobal.EVENT_DISPLAY_REMOVED);
         scheduleTraversalLocked(false);
+
+        if (mDisplayWindowPolicyControllers.contains(displayId)) {
+            final IVirtualDevice virtualDevice = mDisplayWindowPolicyControllers.removeReturnOld(
+                    displayId).first;
+            if (virtualDevice != null) {
+                mHandler.post(() -> {
+                    getLocalService(VirtualDeviceManagerInternal.class)
+                            .onVirtualDisplayRemoved(virtualDevice, displayId);
+                });
+            }
+        }
     }
 
     private void handleLogicalDisplaySwappedLocked(@NonNull LogicalDisplay display) {