From: Witold Kręcicki <wpk@isc.org>
Date: Sat, 7 Dec 2019 22:44:16 +0000 (+0100)
Subject: always return true in ns_interfacemgr_listeningon if interfacemgr is shutting down
X-Git-Tag: v9.15.7~20^2~6
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b804d3a395fd0038670f51df6269efcbeb67088a;p=thirdparty%2Fbind9.git

always return true in ns_interfacemgr_listeningon if interfacemgr is shutting down
to avoid deadlocks on shutdown.
---

diff --git a/lib/ns/interfacemgr.c b/lib/ns/interfacemgr.c
index 2dd03a0eee9..3bbeee2a50b 100644
--- a/lib/ns/interfacemgr.c
+++ b/lib/ns/interfacemgr.c
@@ -83,6 +83,7 @@ struct ns_interfacemgr {
 	ISC_LIST(isc_sockaddr_t) listenon;
 	int			backlog;	/*%< Listen queue size */
 	unsigned int		udpdisp;	/*%< UDP dispatch count */
+	atomic_bool		shuttingdown;	/*%< Interfacemgr is shutting down */
 #ifdef USE_ROUTE_SOCKET
 	isc_task_t *		task;
 	isc_socket_t *		route;
@@ -217,6 +218,7 @@ ns_interfacemgr_create(isc_mem_t *mctx,
 	mgr->listenon4 = NULL;
 	mgr->listenon6 = NULL;
 	mgr->udpdisp = udpdisp;
+	atomic_init(&mgr->shuttingdown, false);
 
 	ISC_LIST_INIT(mgr->interfaces);
 	ISC_LIST_INIT(mgr->listenon);
@@ -360,6 +362,7 @@ ns_interfacemgr_shutdown(ns_interfacemgr_t *mgr) {
 	 * consider all interfaces "old".
 	 */
 	mgr->generation++;
+	atomic_store(&mgr->shuttingdown, true);
 #ifdef USE_ROUTE_SOCKET
 	LOCK(&mgr->lock);
 	if (mgr->route != NULL) {
@@ -1230,7 +1233,13 @@ ns_interfacemgr_listeningon(ns_interfacemgr_t *mgr,
 	bool result = false;
 
 	REQUIRE(NS_INTERFACEMGR_VALID(mgr));
-
+	/*
+	 * If the manager is shutting down it's safer to
+	 * return true.
+	 */
+	if (atomic_load(&mgr->shuttingdown)) {
+		return (true);
+	}
 	LOCK(&mgr->lock);
 	for (old = ISC_LIST_HEAD(mgr->listenon);
 	     old != NULL;