diff --git a/lib/isc/lib.c b/lib/isc/lib.c
index bdff8efd35..c0f9d30dba 100644
--- a/lib/isc/lib.c
+++ b/lib/isc/lib.c
@@ -67,6 +67,9 @@ isc__lib_shutdown(void) {
 		return;
 	}
 
+	rcu_barrier();
+	rcu_unregister_thread();
+
 	isc__iterated_hash_shutdown();
 	isc__xml_shutdown();
 	isc__uv_shutdown();
@@ -75,6 +78,4 @@ isc__lib_shutdown(void) {
 	isc__mem_shutdown();
 	isc__mutex_shutdown();
 	isc__os_shutdown();
-	/* should be after isc__mem_shutdown() which calls rcu_barrier() */
-	rcu_unregister_thread();
 }
diff --git a/lib/isc/mem.c b/lib/isc/mem.c
index c1b0ab7331..ff34485ae0 100644
--- a/lib/isc/mem.c
+++ b/lib/isc/mem.c
@@ -434,10 +434,9 @@ isc__mem_initialize(void) {
 
 void
 isc__mem_shutdown(void) {
+	/* should be called after an rcu_barrier() */
 	bool empty;
 
-	rcu_barrier();
-
 	isc__mem_checkdestroyed();
 
 	LOCK(&contextslock);