From 8f4c4fea20da04557d94eab0acbbc681861cce15 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jano=C5=A1=20Gulja=C5=A1?= <janos@users.noreply.github.com>
Date: Mon, 30 Jul 2018 11:44:17 +0200
Subject: [PATCH] p2p: fix rare deadlock in Stop (#17260)

---
 p2p/server.go | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/p2p/server.go b/p2p/server.go
index cdb5b1926e..8f860d8f10 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -340,8 +340,8 @@ func (srv *Server) makeSelf(listener net.Listener, ntab discoverTable) *discover
 // It blocks until all active connections have been closed.
 func (srv *Server) Stop() {
 	srv.lock.Lock()
-	defer srv.lock.Unlock()
 	if !srv.running {
+		srv.lock.Unlock()
 		return
 	}
 	srv.running = false
@@ -350,6 +350,7 @@ func (srv *Server) Stop() {
 		srv.listener.Close()
 	}
 	close(srv.quit)
+	srv.lock.Unlock()
 	srv.loopWG.Wait()
 }