diff --git a/changed.go b/changed.go
index 18c6ab9..df955cb 100644
--- a/changed.go
+++ b/changed.go
@@ -1,10 +1,13 @@
 package config
 
+import "sync"
+
 // this package can provide a trivial way to track which
 // protobufs have been modified and need to be written to disk
 // todo: autogenpb could generate code to work with this
 
 var saveMap map[string]bool
+var saveLock sync.Mutex
 
 func init() {
 	// init() should be avoided, but this package and for making
@@ -13,6 +16,8 @@ func init() {
 }
 
 func SetChanged(name string, b bool) {
+	saveLock.Lock()
+	defer saveLock.Unlock()
 	saveMap[name] = b
 }