diff --git a/hostapd/ctrl_iface.c b/hostapd/ctrl_iface.c
index 6be6c2ab5..aa803533c 100644
--- a/hostapd/ctrl_iface.c
+++ b/hostapd/ctrl_iface.c
@@ -2586,7 +2586,7 @@ hostapd_global_ctrl_iface_fst_attach(struct hapd_interfaces *interfaces,
 		}
 	}
 
-	return EINVAL;
+	return -EINVAL;
 }
 
 
@@ -2608,7 +2608,7 @@ hostapd_global_ctrl_iface_fst_detach(struct hapd_interfaces *interfaces,
 		}
 	}
 
-	return EINVAL;
+	return -EINVAL;
 }
 
 #endif /* CONFIG_FST */