From 5bc29e7388ab723fde3a52e561f3132d5f0cc71c Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Wed, 24 Jun 2020 13:55:56 -0700
Subject: [PATCH] ipn: add missing locking in LocalBackend.NetMap

Looks like it's only used by tests.
---
 ipn/local.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ipn/local.go b/ipn/local.go
index 899f42951..b682f261a 100644
--- a/ipn/local.go
+++ b/ipn/local.go
@@ -769,6 +769,8 @@ func (b *LocalBackend) doSetHostinfoFilterServices(hi *tailcfg.Hostinfo) {
 // NetMap returns the latest cached network map received from
 // controlclient, or nil if no network map was received yet.
 func (b *LocalBackend) NetMap() *controlclient.NetworkMap {
+	b.mu.Lock()
+	defer b.mu.Unlock()
 	return b.netMap
 }