diff --git a/include/osmocom/core/fsm.h b/include/osmocom/core/fsm.h
index 77ebe7c..5e5b091 100644
--- a/include/osmocom/core/fsm.h
+++ b/include/osmocom/core/fsm.h
@@ -224,9 +224,9 @@
 int osmo_fsm_inst_update_id_f(struct osmo_fsm_inst *fi, const char *fmt, ...);
 int osmo_fsm_inst_update_id_f_sanitize(struct osmo_fsm_inst *fi, char replace_with, const char *fmt, ...);
 
-const char *osmo_fsm_event_name(struct osmo_fsm *fsm, uint32_t event);
-const char *osmo_fsm_inst_name(struct osmo_fsm_inst *fi);
-const char *osmo_fsm_state_name(struct osmo_fsm *fsm, uint32_t state);
+const char *osmo_fsm_event_name(const struct osmo_fsm *fsm, uint32_t event);
+const char *osmo_fsm_inst_name(const struct osmo_fsm_inst *fi);
+const char *osmo_fsm_state_name(const struct osmo_fsm *fsm, uint32_t state);
 
 /*! return the name of the state the FSM instance is currently in. */
 static inline const char *osmo_fsm_inst_state_name(struct osmo_fsm_inst *fi)