diff --git a/src/libmsc/mncc_call.c b/src/libmsc/mncc_call.c
index e5fc820..0deb903 100644
--- a/src/libmsc/mncc_call.c
+++ b/src/libmsc/mncc_call.c
@@ -60,7 +60,7 @@
 
 void mncc_call_fsm_init(struct gsm_network *net)
 {
-	osmo_fsm_register(&mncc_call_fsm);
+	OSMO_ASSERT(osmo_fsm_register(&mncc_call_fsm) == 0);
 	gsmnet = net;
 }