diff --git a/lib/isc/include/isc/list.h b/lib/isc/include/isc/list.h
index 508f9fe6a0..e94f42f0e3 100644
--- a/lib/isc/include/isc/list.h
+++ b/lib/isc/include/isc/list.h
@@ -103,7 +103,7 @@
 		(elt)->link.prev = (type *)(-1); \
 		(elt)->link.next = (type *)(-1); \
 		ISC_INSIST((list).head != (elt)); \
-		ISC_INSIST((list).head != (elt)); \
+		ISC_INSIST((list).tail != (elt)); \
 	} while (0)
 
 #define __ISC_LIST_UNLINKUNSAFE(list, elt, link) \