From 0e5dd25fc5c70d656666f6d537e93cf346e7f419 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Witold=20Kr=C4=99cicki?= <wpk@isc.org>
Date: Thu, 3 Jan 2019 13:06:39 +0100
Subject: [PATCH] When a forwarder fails and we're not in a forward-only mode
 we go back to regular resolution. When this happens the fetch timer is
 already running, and we might end up in a situation where we we create a
 fetch for qname-minimized query and after that the timer is triggered and the
 query is retried (fctx_try) - which causes relaunching of qname-minimization
 fetch - and since we already have a qmin fetch for this fctx - assertion
 failure.


diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 8beecbcb07..ea122bd30c 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -4012,6 +4012,7 @@ fctx_try(fetchctx_t *fctx, bool retrying, bool badcache) {
 		options &= ~DNS_FETCHOPT_QMINIMIZE;
 		fctx_increference(fctx);
 		task = res->buckets[bucketnum].task;
+		fctx_stoptimer(fctx);
 		result = dns_resolver_createfetch(fctx->res, &fctx->qminname,
 						  fctx->qmintype, &fctx->domain,
 						  &fctx->nameservers, NULL, NULL, 0,
@@ -4343,13 +4344,12 @@ fctx_timeout(isc_task_t *task, isc_event_t *event) {
 		 * timer.
 		 */
 		result = fctx_starttimer(fctx);
-		if (result != ISC_R_SUCCESS)
+		if (result != ISC_R_SUCCESS) {
 			fctx_done(fctx, result, __LINE__);
-		else
-			/*
-			 * Keep trying.
-			 */
+		} else {
+			/* Keep trying */
 			fctx_try(fctx, true, false);
+		}
 	}
 
 	isc_event_free(&event);
-- 
2.18.1