diff --git a/openbsc/src/bsc_api.c b/openbsc/src/bsc_api.c
index 35babc3..8b3ff8f 100644
--- a/openbsc/src/bsc_api.c
+++ b/openbsc/src/bsc_api.c
@@ -606,6 +606,20 @@
 	if (subsys != SS_LCHAN)
 		return 0;
 
+	/*
+	 * Check if it is any of the signals we handle. We do want
+	 * to do this early as we will need to check the lchan and
+	 * the bsc api in it.
+	 */
+	switch (signal) {
+	case S_LCHAN_UNEXPECTED_RELEASE:
+	case S_LCHAN_ACTIVATE_ACK:
+	case S_LCHAN_ACTIVATE_NACK:
+		break;
+	default:
+		return -1;
+	}
+
 	lchan = (struct gsm_lchan *)signal_data;
 	if (!lchan || !lchan->conn)
 		return 0;