From 1c54274ec137fe97454c043f69f2e6e960b419e7 Mon Sep 17 00:00:00 2001
From: Lyon Hill <lyondhill@gmail.com>
Date: Fri, 8 Nov 2019 15:08:15 -0700
Subject: [PATCH] fix: add locking around timers to avoid race

add locking around access and updates to the stopped field.
---
 clock.go | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/clock.go b/clock.go
index c4c5230..a48e6ac 100644
--- a/clock.go
+++ b/clock.go
@@ -255,8 +255,13 @@ func (t *Timer) Stop() bool {
 		return t.timer.Stop()
 	}
 
+	t.mock.mu.Lock()
 	registered := !t.stopped
+	t.mock.mu.Unlock()
+
 	t.mock.removeClockTimer((*internalTimer)(t))
+	t.mock.mu.Lock()
+	defer t.mock.mu.Unlock()
 	t.stopped = true
 	return registered
 }
@@ -268,12 +273,14 @@ func (t *Timer) Reset(d time.Duration) bool {
 	}
 
 	t.next = t.mock.now.Add(d)
+	t.mock.mu.Lock()
+	defer t.mock.mu.Unlock()
+
 	registered := !t.stopped
 	if t.stopped {
-		t.mock.mu.Lock()
 		t.mock.timers = append(t.mock.timers, (*internalTimer)(t))
-		t.mock.mu.Unlock()
 	}
+
 	t.stopped = false
 	return registered
 }
@@ -288,6 +295,9 @@ func (t *internalTimer) Tick(now time.Time) {
 		t.c <- now
 	}
 	t.mock.removeClockTimer((*internalTimer)(t))
+	t.mock.mu.Lock()
+	defer t.mock.mu.Unlock()
+
 	t.stopped = true
 	gosched()
 }