From 3d36f2b00520911a5769df7b5353d7231972cf67 Mon Sep 17 00:00:00 2001
From: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Mon, 30 Jun 2025 23:33:31 +0000
Subject: [PATCH] Hedge against runaway recursion. See #3130

---
 nmap_dns.cc | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/nmap_dns.cc b/nmap_dns.cc
index 9528a4564..59778ded7 100644
--- a/nmap_dns.cc
+++ b/nmap_dns.cc
@@ -500,8 +500,6 @@ static void write_evt_handler(nsock_pool nsp, nsock_event evt, void *req_v) {
   info record;
   request *req = (request *) req_v;
 
-  req->curr_server->write_busy = 0;
-
   if (nse_status(evt) == NSE_STATUS_SUCCESS) {
     req->curr_server->in_process.push_front(req);
     record.tpreq = req;
@@ -516,6 +514,9 @@ static void write_evt_handler(nsock_pool nsp, nsock_event evt, void *req_v) {
     req->curr_server->to_process.push_front(req);
   }
 
+  // Avoid runaway recursion: when we call do_possible_writes above,
+  // make sure we still are "busy"
+  req->curr_server->write_busy = 0;
 }
 
 static DNS::RECORD_TYPE wire_type(DNS::RECORD_TYPE t) {