diff --git a/include/wlr/render/drm_syncobj.h b/include/wlr/render/drm_syncobj.h
index b847dbd25..bea86d191 100644
--- a/include/wlr/render/drm_syncobj.h
+++ b/include/wlr/render/drm_syncobj.h
@@ -4,6 +4,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 #include <wayland-server-core.h>
+#include <wlr/util/addon.h>
 
 /**
  * A synchronization timeline.
@@ -29,6 +30,8 @@ struct wlr_drm_syncobj_timeline {
 	int drm_fd;
 	uint32_t handle;
 
+	struct wlr_addon_set addons;
+
 	struct {
 		size_t n_refs;
 	} WLR_PRIVATE;
diff --git a/render/drm_syncobj.c b/render/drm_syncobj.c
index f23fd638d..9e5569fb4 100644
--- a/render/drm_syncobj.c
+++ b/render/drm_syncobj.c
@@ -4,6 +4,7 @@
 #include <unistd.h>
 #include <wayland-server-core.h>
 #include <wlr/render/drm_syncobj.h>
+#include <wlr/util/addon.h>
 #include <wlr/util/log.h>
 
 #include "config.h"
@@ -22,6 +23,8 @@ static struct wlr_drm_syncobj_timeline *timeline_create(int drm_fd, uint32_t han
 	timeline->n_refs = 1;
 	timeline->handle = handle;
 
+	wlr_addon_set_init(&timeline->addons);
+
 	return timeline;
 }
 
@@ -72,6 +75,7 @@ void wlr_drm_syncobj_timeline_unref(struct wlr_drm_syncobj_timeline *timeline) {
 		return;
 	}
 
+	wlr_addon_set_finish(&timeline->addons);
 	drmSyncobjDestroy(timeline->drm_fd, timeline->handle);
 	free(timeline);
 }