compositor: Check serial number ordering without overflowing

diff --git a/src/compositor.c b/src/compositor.c
index 4f5388d..9891b3c 100644 (file)
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -2213,7 +2213,7 @@ pointer_set_cursor(struct wl_client *client, struct wl_resource *resource,
                surface = container_of(surface_resource->data,
                                       struct weston_surface, surface);
 
-       if (serial < seat->seat.pointer->focus_serial)
+       if (seat->seat.pointer->focus_serial - serial > UINT32_MAX / 2)
                return;
 
        if (surface && surface != seat->sprite) {