From 993002cebf2d8150c212f6a6d9274aeecade9594 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 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index d114180401..ca0c62cbbe 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -5335,9 +5335,9 @@ validated(void *arg) {
 	addrinfo = valarg->addrinfo;
 
 	message = val->message;
-	fctx->vresult = val->result;
 
 	LOCK(&fctx->lock);
+	fctx->vresult = val->result;
 	ISC_LIST_UNLINK(fctx->validators, val, link);
 	fctx->validator = NULL;
 	UNLOCK(&fctx->lock);