From d7a257b39177eea973a02f74cd808eef1f89ca98 Mon Sep 17 00:00:00 2001
From: greatroar <61184462+greatroar@users.noreply.github.com>
Date: Mon, 30 Mar 2020 15:10:08 +0200
Subject: [PATCH] lib/util: Fix potential data race (#6477)

Co-authored-by: greatroar <@>
---
 lib/util/utils.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/util/utils.go b/lib/util/utils.go
index 4990af7c7..1851aa035 100644
--- a/lib/util/utils.go
+++ b/lib/util/utils.go
@@ -255,8 +255,12 @@ func (s *service) Stop() {
 	default:
 		s.cancel()
 	}
+
+	// Cache s.stopped in a variable while we hold the mutex
+	// to prevent a data race with Serve's resetting it.
+	stopped := s.stopped
 	s.mut.Unlock()
-	<-s.stopped
+	<-stopped
 }
 
 func (s *service) Error() error {