diff --git a/src/gsm/gsm0411_smc.c b/src/gsm/gsm0411_smc.c
index c44423d..4c08365 100644
--- a/src/gsm/gsm0411_smc.c
+++ b/src/gsm/gsm0411_smc.c
@@ -184,8 +184,7 @@
 	/* 5.2.3.1.2: enter MO-wait for CP-ACK */
 	/* 5.2.3.2.3: enter MT-wait for CP-ACK */
 	new_cp_state(inst, GSM411_CPS_WAIT_CP_ACK);
-	inst->cp_timer.data = inst;
-	inst->cp_timer.cb = cp_timer_expired;
+	osmo_timer_setup(&inst->cp_timer, cp_timer_expired, inst);
 	/* 5.3.2.1: Set Timer TC1A */
 	osmo_timer_schedule(&inst->cp_timer, inst->cp_tc1, 0);
 	/* clone cp_msg */