From: Ondřej Surý <ondrej@isc.org>
Date: Tue, 17 Jan 2023 06:18:16 +0000 (+0100)
Subject: Detach the views in zone_shutdown(), not in zone_free()
X-Git-Tag: v9.19.10~39^2~2
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=13bb8212804ce385010387d681a6623481921023;p=thirdparty%2Fbind9.git

Detach the views in zone_shutdown(), not in zone_free()

The .view (and possibly .prev_view) would be kept attached to the
removed zone until the zone is fully removed from the memory in
zone_free().  If this process is delayed because server is busy
something else like doing constant `rndc reconfig`, it could take
seconds to detach the view, possibly keeping multiple dead views in the
memory.  This could quickly lead to a massive memory bloat.

Release the views early in the zone_shutdown() call, and don't wait
until the zone is freed.
---

diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 28aeb00e047..411756d9cbe 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -1246,6 +1246,8 @@ zone_free(dns_zone_t *zone) {
 	INSIST(zone->readio == NULL);
 	INSIST(zone->statelist == NULL);
 	INSIST(zone->writeio == NULL);
+	INSIST(zone->view == NULL);
+	INSIST(zone->prev_view == NULL);
 
 	if (zone->task != NULL) {
 		isc_task_detach(&zone->task);
@@ -1253,12 +1255,6 @@ zone_free(dns_zone_t *zone) {
 	if (zone->loadtask != NULL) {
 		isc_task_detach(&zone->loadtask);
 	}
-	if (zone->view != NULL) {
-		dns_view_weakdetach(&zone->view);
-	}
-	if (zone->prev_view != NULL) {
-		dns_view_weakdetach(&zone->prev_view);
-	}
 
 	/* Unmanaged objects */
 	while (!ISC_LIST_EMPTY(zone->setnsec3param_queue)) {
@@ -14737,6 +14733,15 @@ zone_shutdown(void *arg) {
 
 	LOCK_ZONE(zone);
 	INSIST(zone != zone->raw);
+
+	/* Detach the views early, we don't need them anymore */
+	if (zone->view != NULL) {
+		dns_view_weakdetach(&zone->view);
+	}
+	if (zone->prev_view != NULL) {
+		dns_view_weakdetach(&zone->prev_view);
+	}
+
 	if (linked) {
 		isc_refcount_decrement(&zone->irefs);
 	}