[PATCH weston] compositor: ignore unmapped sub-surfaces for view_list

[Jason Ekstrand]

Yeah, I think this looks ok.

Reviewed-by: Jason Ekstrand <jason at jlekstrand.net>


On Mon, Jul 28, 2014 at 4:06 AM, Pekka Paalanen <ppaalanen at gmail.com> wrote:

> From: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
>
> It looks like that in the great conversion introducing weston_view, one
> conditional was forgotten from the code that builds the global flat list
> of views. Sub-surfaces are added to the view list specially, as they are
> not governed by their presence in a layer's view list, and therefore
> need an explicit check for mappedness.
>
> The bug, missing the explicit check, caused sub-surfaces to enter the
> global view_list regardless of their state. This lead to the pointer
> focus picking code processing them, and as the input region defaults to
> infinite, picking these unmapped surfaces. Clients then get confused
> about the wl_pointer.enter events with unexpected wl_surface.
>
> To trigger this issue, it is enough to just create one additional
> wl_surface and make it a sub-surface of a main surface that is or gets
> mapped. Literally, just a wl_subsomcpositor_get_subsurface() call is
> enough. At some point later, the unmapped sub-surface will get pointer
> focus, depending on view stacking order.
>
> Fix the issue by adding a is_mapped check when building the view_list.
>
> Note, that 95ec0f95aa2df74c2da19e7dda24528fa8f765cc accidentally also
> prevents this bug from happening, because it adds a test against the
> transform.masked_boundingbox in weston_compositor_pick_view().
>
> Reported-by: George Kiagiadakis <george.kiagiadakis at collabora.com>
> Signed-off-by: Pekka Paalanen <pekka.paalanen at collabora.co.uk>
> Cc: Jason Ekstrand <jason.ekstrand at intel.com>
> ---
>  src/compositor.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/src/compositor.c b/src/compositor.c
> index 02f569f..1e17583 100644
> --- a/src/compositor.c
> +++ b/src/compositor.c
> @@ -1751,6 +1751,9 @@ view_list_add_subsurface_view(struct
> weston_compositor *compositor,
>         struct weston_subsurface *child;
>         struct weston_view *view = NULL, *iv;
>
> +       if (!weston_surface_is_mapped(sub->surface))
> +               return;
> +
>         wl_list_for_each(iv, &sub->unused_views, surface_link) {
>                 if (iv->geometry.parent == parent) {
>                         view = iv;
> --
> 1.8.5.5
>
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