diff --git a/include/openbsc/signal.h b/include/openbsc/signal.h
index c2cf46a..4a583f6 100644
--- a/include/openbsc/signal.h
+++ b/include/openbsc/signal.h
@@ -37,6 +37,7 @@
 	SS_SMS,
 	SS_ABISIP,
 	SS_NM,
+	SS_LCHAN,
 };
 
 /* SS_PAGING signals */
@@ -55,6 +56,16 @@
 	S_NM_FAIL_REP,		/* GSM 12.21 failure event report */
 };
 
+/* SS_LCHAN signals */
+enum signal_lchan {
+	/*
+	 * The lchan got freed with an use_count != 0 and error
+	 * recovery needs to be carried out from within the
+	 * signal handler.
+	 */
+	S_LCHAN_UNEXPECTED_RELEASE,
+};
+
 typedef int signal_cbfn(unsigned int subsys, unsigned int signal,
 			void *handler_data, void *signal_data);