diff --git a/CHANGES b/CHANGES
index e86a6ab7d1..cd6081b3d3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,5 @@
+ 937.	[bug]		A race when shutting down a zone could trigger a
+			INSIST() failure. [RT #1034]
 
  936.	[func]		Warn about IPv4 addresses that are not complete
 			dotted quads. [RT #1084]
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 0f5d1fa562..119c361912 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: zone.c,v 1.329 2001/07/11 23:15:14 marka Exp $ */
+/* $Id: zone.c,v 1.330 2001/07/17 02:49:44 marka Exp $ */
 
 #include <config.h>
 
@@ -560,12 +560,11 @@ zone_free(dns_zone_t *zone) {
 	REQUIRE(isc_refcount_current(&zone->erefs) == 0);
 	REQUIRE(zone->irefs == 0);
 	REQUIRE(!LOCKED_ZONE(zone));
+	REQUIRE(zone->timer == NULL);
 
 	/*
 	 * Managed objects.  Order is important.
 	 */
-	if (zone->timer != NULL)
-		isc_timer_detach(&zone->timer);
 	if (zone->request != NULL)
 		dns_request_destroy(&zone->request); /* XXXMPA */
 	INSIST(zone->readio == NULL);
@@ -1545,6 +1544,7 @@ zone_iattach(dns_zone_t *source, dns_zone_t **target) {
 	REQUIRE(LOCKED_ZONE(source));
 	REQUIRE(DNS_ZONE_VALID(source));
 	REQUIRE(target != NULL && *target == NULL);
+	INSIST(source->irefs + isc_refcount_current(&source->erefs) > 0);
 	source->irefs++;
 	INSIST(source->irefs != 0);
 	*target = source;
@@ -3668,7 +3668,6 @@ ns_query(dns_zone_t *zone, dns_rdataset_t *soardataset, dns_stub_t *stub) {
 static void
 zone_shutdown(isc_task_t *task, isc_event_t *event) {
 	dns_zone_t *zone = (dns_zone_t *) event->ev_arg;
-	isc_result_t result;
 	isc_boolean_t free_needed;
 
 	UNUSED(task);
@@ -3720,9 +3719,9 @@ zone_shutdown(isc_task_t *task, isc_event_t *event) {
 	notify_cancel(zone);
 
 	if (zone->timer != NULL) {
-		result = isc_timer_reset(zone->timer, isc_timertype_inactive,
-					 NULL, NULL, ISC_TRUE);
-		RUNTIME_CHECK(result == ISC_R_SUCCESS);
+		isc_timer_detach(&zone->timer);
+		INSIST(zone->irefs > 0);
+		zone->irefs--;
 	}
 
 	if (zone->view != NULL)
@@ -5403,6 +5402,11 @@ dns_zonemgr_managezone(dns_zonemgr_t *zmgr, dns_zone_t *zone) {
 				  &zone->timer);
 	if (result != ISC_R_SUCCESS)
 		goto cleanup_task;
+	/*
+	 * The timer "holds" a iref.
+	 */
+	zone->irefs++;
+	INSIST(zone->irefs != 0);
 
 	ISC_LIST_APPEND(zmgr->zones, zone, link);
 	zone->zmgr = zmgr;