diff --git a/libweston/pixman-renderer.c b/libweston/pixman-renderer.c
index 9150fa402..ec7ddf5e6 100644
--- a/libweston/pixman-renderer.c
+++ b/libweston/pixman-renderer.c
@@ -64,6 +64,9 @@ struct pixman_surface_state {
 };
 
 struct pixman_renderbuffer {
+#if !defined(NDEBUG)
+	struct weston_output *output;
+#endif
 	pixman_region32_t damage;
 	pixman_image_t *image;
 	bool stale;
@@ -637,7 +640,8 @@ pixman_renderer_repaint_output(struct weston_output *output,
 	struct pixman_output_state *po = get_output_state(output);
 	struct pixman_renderbuffer *rb;
 
-	assert(renderbuffer);
+	assert(po);
+	assert(((struct pixman_renderbuffer *) renderbuffer)->output == output);
 
 	/* Accumulate damage in all renderbuffers */
 	wl_list_for_each(rb, &po->renderbuffer_list, link) {
@@ -940,6 +944,9 @@ pixman_renderer_create_renderbuffer(struct weston_output *output,
 		return NULL;
 	}
 
+#if !defined(NDEBUG)
+	renderbuffer->output = output;
+#endif
 	pixman_region32_init(&renderbuffer->damage);
 	pixman_region32_copy(&renderbuffer->damage, &output->region);
 	renderbuffer->discarded_cb = discarded_cb;
@@ -1185,6 +1192,8 @@ pixman_renderer_output_create(struct weston_output *output,
 		.height = options->fb_size.height
 	};
 
+	assert(!get_output_state(output));
+
 	po = zalloc(sizeof *po);
 	if (po == NULL)
 		return -1;
@@ -1215,6 +1224,8 @@ pixman_renderer_output_destroy(struct weston_output *output)
 {
 	struct pixman_output_state *po = get_output_state(output);
 
+	assert(po);
+
 	if (po->shadow_image)
 		pixman_image_unref(po->shadow_image);
 
@@ -1227,6 +1238,7 @@ pixman_renderer_output_destroy(struct weston_output *output)
 	pixman_renderer_discard_renderbuffers(po, true);
 
 	free(po);
+	output->renderer_state = NULL;
 }
 
 static struct pixman_renderer_interface pixman_renderer_interface = {
diff --git a/libweston/renderer-gl/gl-renderer.c b/libweston/renderer-gl/gl-renderer.c
index 32bc329a3..2a963b1df 100644
--- a/libweston/renderer-gl/gl-renderer.c
+++ b/libweston/renderer-gl/gl-renderer.c
@@ -122,6 +122,7 @@ struct gl_renderbuffer_dmabuf {
 };
 
 struct gl_renderbuffer {
+	struct weston_output *output;
 	enum gl_renderbuffer_type type;
 	pixman_region32_t damage;
 	enum gl_border_status border_damage;
@@ -785,6 +786,7 @@ gl_renderbuffer_init(struct gl_renderbuffer *renderbuffer,
 {
 	struct gl_output_state *go = get_output_state(output);
 
+	renderbuffer->output = output;
 	renderbuffer->type = type;
 	pixman_region32_init(&renderbuffer->damage);
 	pixman_region32_copy(&renderbuffer->damage, &output->region);
@@ -2529,14 +2531,20 @@ gl_renderer_repaint_output(struct weston_output *output,
 	struct gl_renderer *gr = get_renderer(compositor);
 	static int errored;
 	struct weston_paint_node *pnode;
-	const int32_t area_y =
-		is_y_flipped(go) ? go->fb_size.height - go->area.height - go->area.y : go->area.y;
+	int32_t area_y;
 	struct gl_renderbuffer *rb;
 
+	assert(go);
+	assert(!renderbuffer ||
+	       ((struct gl_renderbuffer *) renderbuffer)->output == output);
+	assert(renderbuffer || go->egl_surface != EGL_NO_SURFACE);
 	assert(output->from_blend_to_output_by_backend ||
 	       output->color_outcome->from_blend_to_output == NULL ||
 	       shadow_exists(go));
 
+	area_y = is_y_flipped(go) ?
+		go->fb_size.height - go->area.height - go->area.y : go->area.y;
+
 	if (use_output(output) < 0)
 		return;
 
@@ -4273,6 +4281,8 @@ gl_renderer_output_create(struct weston_output *output,
 	struct gl_renderer *gr = get_renderer(output->compositor);
 	const struct weston_testsuite_quirks *quirks;
 
+	assert(!get_output_state(output));
+
 	quirks = &output->compositor->test_data.test_quirks;
 
 	go = zalloc(sizeof *go);
@@ -4441,6 +4451,8 @@ gl_renderer_output_destroy(struct weston_output *output)
 	struct gl_output_state *go = get_output_state(output);
 	struct timeline_render_point *trp, *tmp;
 
+	assert(go);
+
 	if (shadow_exists(go))
 		gl_fbo_texture_fini(&go->shadow_fb, &go->shadow_tex);
 
@@ -4465,6 +4477,7 @@ gl_renderer_output_destroy(struct weston_output *output)
 	gl_renderer_discard_renderbuffers(go, true);
 
 	free(go);
+	output->renderer_state = NULL;
 }
 
 static int