If one would end up with an actor attached to mapped actor, where the
attached actor doesn't itself have an up to date stage view list while
listening on the stage for updating, when clearing the stage views of
the list, anything that would query the stage views list at this time
would end up accessing freed memory.
This could happen if
1) An actor was added to a newly created container actor attached to
the stage
2) The actor got a timeline attached to it
3) The actor was moved to a container that already was mapped
4) A hotplug happened
After (1) both the container and actor would not have any stage views.
After (2) the timeline would listen on the stage for stage views
updates. After (3) the actor would still listen on the stage for stage
views updates. When (4) happened, the actor would be signalled when the
stage got its stage view cleared, at which point it would traverse up
its actor's tree finding an appropriate stage view to base its animation
on. The problem here would be that it'd query the already mapped
container and its yet-to-be-cleared stage view list, resulting in
use-after free, resulting in for example the following backtrace:
0) g_type_check_instance_cast ()
1) CLUTTER_STAGE_VIEW ()
2) clutter_actor_pick_frame_clock ()
3) clutter_actor_pick_frame_clock ()
4) update_frame_clock ()
5) on_frame_clock_actor_stage_views_changed ()
6) g_closure_invoke ()
7) signal_emit_unlocked_R ()
8) g_signal_emit_valist ()
9) g_signal_emit ()
10) clear_stage_views_cb ()
11) _clutter_actor_traverse_depth ()
12) _clutter_actor_traverse ()
13) clutter_actor_clear_stage_views_recursive ()
14) clutter_stage_clear_stage_views ()
...
Avoid this issue by making sure that we don't emit 'stage-views-changed'
signals while the actor tree is in an invalid state. While we now end up
traversing tree twice, it doesn't change the Big-O notation. It has not
been measured whether this has any noticible performance impact.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/1950
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2025>
This will require some symbol exporting, but the benefit is that have
better control of what external test cases can do in terms of creating
more testing specific contexts.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1861>
It'll be part of and owned by MetaContext, intending to replace
`meta_is_wayland_compositor()`, but place it in a new file for public
enums so that it can be used from wherever.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1861>
This makes it possible to pass custom properties to backends when
constructing tests. This will be used to create "headless" native
backend instances for testing the headless native backend.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1698>
Add a test case to check whether the stage views and frame clocks are
all correctly freed after working with timelines a bit and then
hotplugging and removing all monitors.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1632>
It'd happen that the test runner would get CPU starved, and not see the
frame-clock changed notification before the timeline stopped. Decrease
the risk for this by moving the initial position of the actor having its
position transitioned to be closer to the view edge. This means the
frame clock will be changed earlier, increasing the chance of the
timeline not stopping before the relayout happens.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1555
Test that if a timeline got its frame clock from a parent of the
associated actor, if that actor moves across the stage so that the stage
views changes and thus the would be picked frame clock too, this is
noticed by the timeline so that it also changes to the correct frame
clock.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1404
Timelines where the frame clock was picked from a parent of the
associated actor didn't get notified about any stage views changes, as
it only listened on the associated actor. If that actor didn't actually
get its stage views changed (because it went from empty to empty), we'd
end up with a stale frame clock, leading to crashes.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1404
Currently there is a point in between hot plug, and when the stage view
list is up to date. The check also tests for this behaviour; would this
ever change, the test should be adapted to deal with this too.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285
Replace the default master clock with multiple frame clocks, each
driving its own stage view. As each stage view represents one CRTC, this
means we draw each CRTC with its own designated frame clock,
disconnected from all the others.
For example this means we when using the native backend will never need
to wait for one monitor to vsync before painting another, so e.g. having
a 144 Hz monitor next to a 60 Hz monitor, things including both Wayland
and X11 applications and shell UI will be able to render at the
corresponding monitor refresh rate.
This also changes a warning about missed frames when sending
_NETWM_FRAME_TIMINGS messages to a debug log entry, as it's expected
that we'll start missing frames e.g. when a X11 window (via Xwayland) is
exclusively within a stage view that was not painted, while another one
was, still increasing the global frame clock.
Addititonally, this also requires the X11 window actor to schedule
timeouts for _NET_WM_FRAME_DRAWN/_NET_WM_FRAME_TIMINGS event emitting,
if the actor wasn't on any stage views, as now we'll only get the frame
callbacks on actors when they actually were painted, while in the past,
we'd invoke that vfunc when anything was painted.
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/903
Closes: https://gitlab.gnome.org/GNOME/mutter/-/issues/3https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1285
When a transition is created for the allocation change, it will delay
the new allocation box getting set depending on transition details.
This, however, means that e.g. the 'needs_allocation' flag never gets
cleared if a transition is created, causing other parts of the code to
get confused thinking it didn't pass through a layout step before paint.
Fix this by calling clutter_actor_allocate_internal() with the current
allocation box if a transition was created, so that we'll properly clear
'needs_allocation' flag.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1345
Test that the stage-views list of ClutterActor is correct when moving an
actor, reparenting it, or hiding an actor up the hierarchy. Also test
that the "stage-views-changed" signal works as expected.
Don't test actor transforms for now because those aren't supported yet.
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1196
