From 1a5f560387003a5c017eb063a21424a38377f754 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ond=C5=99ej=20Sur=C3=BD?= <ondrej@isc.org>
Date: Thu, 19 Mar 2026 03:42:08 +0100
Subject: [PATCH] Fix data race on fctx->vresult in validated()

Move the write to fctx->vresult after LOCK(&fctx->lock).  The field was
being set before acquiring the lock, but dns_resolver_logfetch() reads
it under the same lock from another thread.

(cherry picked from commit a2bd8339095c99b4f0faea0f1bc39128c048c3aa)
---
 lib/dns/resolver.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 1bacec6470..b436119613 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -5662,6 +5662,7 @@ validated(isc_task_t *task, isc_event_t *event) {
 
 	bucketnum = fctx->bucketnum;
 	LOCK(&res->buckets[bucketnum].lock);
+	fctx->vresult = vevent->result;
 	ISC_LIST_UNLINK(fctx->validators, vevent->validator, link);
 	fctx->validator = NULL;
 	UNLOCK(&res->buckets[bucketnum].lock);