diff --git a/server/schedulers/hot_region_config.go b/server/schedulers/hot_region_config.go
index 76a33f1576b..22d7dc1f6f5 100644
--- a/server/schedulers/hot_region_config.go
+++ b/server/schedulers/hot_region_config.go
@@ -174,8 +174,8 @@ func (conf *hotRegionSchedulerConfig) GetEnableForTiFlash() bool {
 }
 
 func (conf *hotRegionSchedulerConfig) SetEnableForTiFlash(enable bool) {
-	conf.RLock()
-	defer conf.RUnlock()
+	conf.Lock()
+	defer conf.Unlock()
 	conf.EnableForTiFlash = enable
 }
 
@@ -211,7 +211,7 @@ func (conf *hotRegionSchedulerConfig) handleSetConfig(w http.ResponseWriter, r *
 	}
 	newc, _ := json.Marshal(conf)
 	if !bytes.Equal(oldc, newc) {
-		conf.persist()
+		conf.persistLocked()
 		rd.Text(w, http.StatusOK, "success")
 	}
 
@@ -235,11 +235,10 @@ func (conf *hotRegionSchedulerConfig) handleSetConfig(w http.ResponseWriter, r *
 	rd.Text(w, http.StatusBadRequest, "config item not found")
 }
 
-func (conf *hotRegionSchedulerConfig) persist() error {
+func (conf *hotRegionSchedulerConfig) persistLocked() error {
 	data, err := schedule.EncodeConfig(conf)
 	if err != nil {
 		return err
-
 	}
 	return conf.storage.SaveScheduleConfig(HotRegionName, data)
 }