From a4f7024e0af60c548ec1c066ef77e0b2fda2cb21 Mon Sep 17 00:00:00 2001
From: Dmitriy Vyukov <dvyukov@google.com>
Date: Fri, 13 Jan 2012 22:22:03 +0400
Subject: [PATCH] cmd/go: fix data race during build Fixes #2695.

R=golang-dev, mpimenov, minux.ma, rsc
CC=golang-dev
https://golang.org/cl/5545052
---
 src/cmd/go/build.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index 4a046391db..77a64f406e 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -873,6 +873,8 @@ func (b *builder) runOut(dir string, desc string, cmdargs ...interface{}) ([]byt
 
 // mkdir makes the named directory.
 func (b *builder) mkdir(dir string) error {
+	b.exec.Lock()
+	defer b.exec.Unlock()
 	// We can be a little aggressive about being
 	// sure directories exist.  Skip repeated calls.
 	if b.mkdirCache[dir] {
-- 
2.50.0