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)

diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index d114180401c644c80082bdd504091906efea4535..ca0c62cbbeaed847a903f0817f472db6c8ad3315 100644 (file)
--- 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);