From 120e6eab2c4642543ca8f7f0ad4c3e9798eb1cd4 Mon Sep 17 00:00:00 2001
From: Audrius Butkevicius <audrius.butkevicius@gmail.com>
Date: Wed, 8 Feb 2017 22:31:19 +0000
Subject: [PATCH] lib/sync: Fix a race in unlocker logging (fixes #3884)

Other routines use atomics, hence even if we are under a lock, we should
too.

We might atomically store with
Not sure how it happens, but it's between lines

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3974
---
 lib/sync/sync.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/sync/sync.go b/lib/sync/sync.go
index 783ae2526..8035c7594 100644
--- a/lib/sync/sync.go
+++ b/lib/sync/sync.go
@@ -123,7 +123,7 @@ func (m *loggedRWMutex) Lock() {
 
 	atomic.StoreInt32(&m.logUnlockers, 1)
 	m.RWMutex.Lock()
-	m.logUnlockers = 0
+	atomic.StoreInt32(&m.logUnlockers, 0)
 
 	holder := getHolder()
 	m.holder.Store(holder)