compositor: Destroy window actors list on destruction

When the compositor is destroyed we should cleanup the list of window actors we
created and destroy them.
Since all the actors are added to the window_group or top_window_group we can
just destroy these containers (together with the feedback_group), and simply
free the windows list.

This is particularly needed under X11 because before we destroy the display, we
might do some cleanups as detaching the surface pixmaps and freeing the damages
and if this happens at later point (for example when triggered by garbage
collector in gnome-shell), we might crash because the x11 dpy reference is
already gone.

Destroying the window actors instead, ensures we avoid any further call to X11
related functions and that we release the actors XServer resources.

Fixes https://gitlab.gnome.org/GNOME/mutter/issues/576


(cherry picked from commit 7718e67f5c0c78ed93e9ad04e7254b6db70a0337)

1 files changed, 17 insertions, 0 deletions

diff --git a/src/compositor/compositor.c b/src/compositor/compositor.c
index 176028b71..a7b23ba3c 100644
--- a/src/compositor/compositor.c
+++ b/src/compositor/compositor.c
@@ -90,6 +90,10 @@ on_presented (ClutterStage     *stage,
               ClutterFrameInfo *frame_info,
               MetaCompositor   *compositor);
 
+static void
+on_top_window_actor_destroyed (MetaWindowActor *window_actor,
+                               MetaCompositor  *compositor);
+
 static gboolean
 is_modal (MetaDisplay *display)
 {
@@ -132,6 +136,19 @@ meta_compositor_destroy (MetaCompositor *compositor)
   clutter_threads_remove_repaint_func (compositor->pre_paint_func_id);
   clutter_threads_remove_repaint_func (compositor->post_paint_func_id);
 
+  if (compositor->top_window_actor)
+    {
+      g_signal_handlers_disconnect_by_func (compositor->top_window_actor,
+                                            on_top_window_actor_destroyed,
+                                            compositor);
+      compositor->top_window_actor = NULL;
+    }
+
+  g_clear_pointer (&compositor->window_group, clutter_actor_destroy);
+  g_clear_pointer (&compositor->top_window_group, clutter_actor_destroy);
+  g_clear_pointer (&compositor->feedback_group, clutter_actor_destroy);
+  g_clear_pointer (&compositor->windows, g_list_free);
+
   if (compositor->have_x11_sync_object)
     meta_sync_ring_destroy ();
 }