fix(dnsdist): fix crash on empty selected backend

diff --git a/pdns/dnsdistdist/dnsdist.cc b/pdns/dnsdistdist/dnsdist.cc
index 718e5849047cbe6b70b66d8c37bd34d1a6db4624..c424d7e0a8f6071c5ad54cc1c675df4eebe6c0cd 100644 (file)
--- a/pdns/dnsdistdist/dnsdist.cc
+++ b/pdns/dnsdistdist/dnsdist.cc
@@ -1465,7 +1465,7 @@ static ServerPolicy::SelectedBackend selectBackendForOutgoingQuery(DNSQuestion&
   const auto& servers = serverPool.getServers();
   auto selectedBackend = policy.getSelectedBackend(servers, dnsQuestion);
 
-  if (auto tracer = dnsQuestion.ids.getTracer(); tracer != nullptr && dnsQuestion.ids.tracingEnabled) {
+  if (auto tracer = dnsQuestion.ids.getTracer(); tracer != nullptr && selectedBackend && dnsQuestion.ids.tracingEnabled) {
     tracer->setSpanAttribute(closer.getSpanID(), "backend.name", AnyValue{selectedBackend->getNameWithAddr()});
     tracer->setSpanAttribute(closer.getSpanID(), "backend.id", AnyValue{boost::uuids::to_string(selectedBackend->getID())});
   }