diff --git a/src/dns_client.c b/src/dns_client.c
index d387aaf..99575f6 100644
--- a/src/dns_client.c
+++ b/src/dns_client.c
@@ -448,6 +448,10 @@ void _dns_client_query_remove(struct dns_query_struct *query)
 {
 	/* remove query from period check list, and release reference*/
 	pthread_mutex_lock(&client.domain_map_lock);
+	if (list_empty(&query->dns_request_list)) {
+		pthread_mutex_unlock(&client.domain_map_lock);
+		return;
+	}
 	list_del_init(&query->dns_request_list);
 	hash_del(&query->domain_node);
 	pthread_mutex_unlock(&client.domain_map_lock);
diff --git a/src/dns_server.c b/src/dns_server.c
index e1d2620..56a75dc 100644
--- a/src/dns_server.c
+++ b/src/dns_server.c
@@ -362,7 +362,7 @@ int _dns_server_request_complete(struct dns_request *request)
 
 	_dns_reply(request);
 
-	return ret;
+	return 0;
 }
 
 void _dns_server_request_release(struct dns_request *request);
@@ -387,7 +387,7 @@ void _dns_server_request_release(struct dns_request *request)
 	int refcnt = atomic_dec_return(&request->refcnt);
 	if (refcnt) {
 		if (refcnt < 0) {
-			tlog(TLOG_ERROR, "BUG: refcnt is %d", refcnt);
+			tlog(TLOG_ERROR, "BUG: refcnt is %d, domain %s", refcnt, request->domain);
 			abort();
 		}
 		return;
diff --git a/src/lib/art.c b/src/lib/art.c
index 9caf0f3..f936e81 100644
--- a/src/lib/art.c
+++ b/src/lib/art.c
@@ -384,7 +384,7 @@ art_leaf* art_maximum(art_tree *t) {
 }
 
 static art_leaf* make_leaf(const unsigned char *key, int key_len, void *value) {
-    art_leaf *l = (art_leaf*)calloc(1, sizeof(art_leaf)+key_len);
+    art_leaf *l = (art_leaf*)calloc(1, sizeof(art_leaf)+key_len+1);
     l->value = value;
     l->key_len = key_len;
     memcpy(l->key, key, key_len);