diff --git a/pjmedia/src/pjmedia/transport_loop.c b/pjmedia/src/pjmedia/transport_loop.c
index 37e6f18cd5..df49a3655c 100644
--- a/pjmedia/src/pjmedia/transport_loop.c
+++ b/pjmedia/src/pjmedia/transport_loop.c
@@ -187,6 +187,7 @@ pjmedia_transport_loop_create2(pjmedia_endpt *endpt,
     if (status != PJ_SUCCESS)
         return status;
 
+    tp->base.grp_lock = grp_lock;
     pj_grp_lock_add_ref(grp_lock);
     pj_grp_lock_add_handler(grp_lock, pool, tp, &tp_loop_on_destroy);