From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Wed, 14 May 2025 22:18:38 +0000 (+0900)
Subject: resolve: exit from loop for transactions when transactions has been regenerated
X-Git-Tag: v258-rc1~342
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5814acca9aa4354d121de4bf174851f092a6b643;p=thirdparty%2Fsystemd.git

resolve: exit from loop for transactions when transactions has been regenerated

Fixes #37458.
---

diff --git a/src/resolve/resolved-dns-query.c b/src/resolve/resolved-dns-query.c
index ea8236cec0c..3fd87d4b902 100644
--- a/src/resolve/resolved-dns-query.c
+++ b/src/resolve/resolved-dns-query.c
@@ -210,6 +210,8 @@ static int dns_query_candidate_go(DnsQueryCandidate *c) {
         /* Let's keep a reference to the query while we're operating */
         keep_c = dns_query_candidate_ref(c);
 
+        uint64_t generation = c->generation;
+
         /* Start the transactions that are not started yet */
         SET_FOREACH(t, c->transactions) {
                 if (t->state != DNS_TRANSACTION_NULL)
@@ -219,6 +221,13 @@ static int dns_query_candidate_go(DnsQueryCandidate *c) {
                 if (r < 0)
                         return r;
 
+                if (c->generation != generation)
+                        /* The transaction has been completed, and dns_transaction_complete() ->
+                         * dns_query_candidate_notify() has been already called. Moreover, the query
+                         * candidate has been regenerated, and the query should be already restarted.
+                         * Let's exit from the loop now. */
+                        return 0;
+
                 n++;
         }
 
@@ -280,6 +289,8 @@ static int dns_query_candidate_setup_transactions(DnsQueryCandidate *c) {
 
         dns_query_candidate_stop(c);
 
+        c->generation++;
+
         if (c->query->question_bypass) {
                 /* If this is a bypass query, then pass the original query packet along to the transaction */
 
diff --git a/src/resolve/resolved-dns-query.h b/src/resolve/resolved-dns-query.h
index 9eec6d87d16..2aea9ad6600 100644
--- a/src/resolve/resolved-dns-query.h
+++ b/src/resolve/resolved-dns-query.h
@@ -10,6 +10,7 @@
 typedef struct DnsQueryCandidate {
         unsigned n_ref;
         int error_code;
+        uint64_t generation;
 
         DnsQuery *query;
         DnsScope *scope;