From c37d6fc01a8b70ea3686a81c2acf9d3da0b5ef09 Mon Sep 17 00:00:00 2001
From: Konstantin Lebedev <9497591+kmlebedev@users.noreply.github.com>
Date: Thu, 1 Sep 2022 22:34:06 +0500
Subject: [PATCH] avoid data race on grace.hooks (#3572)

https://github.com/seaweedfs/seaweedfs/issues/3564
---
 weed/util/grace/signal_handling.go | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/weed/util/grace/signal_handling.go b/weed/util/grace/signal_handling.go
index fc7afcad9..24d2b184f 100644
--- a/weed/util/grace/signal_handling.go
+++ b/weed/util/grace/signal_handling.go
@@ -12,7 +12,7 @@ import (
 
 var signalChan chan os.Signal
 var hooks = make([]func(), 0)
-var hookLock sync.Mutex
+var hookLock sync.RWMutex
 
 func init() {
 	signalChan = make(chan os.Signal, 1)
@@ -27,7 +27,9 @@ func init() {
 		// syscall.SIGQUIT,
 	)
 	go func() {
-		for _ = range signalChan {
+		hookLock.RLock()
+		defer hookLock.RUnlock()
+		for range signalChan {
 			for _, hook := range hooks {
 				hook()
 			}