diff --git a/samples/statfs/statfs.go b/samples/statfs/statfs.go
index c9e98e6..a1a39e0 100644
--- a/samples/statfs/statfs.go
+++ b/samples/statfs/statfs.go
@@ -78,6 +78,9 @@ func dirAttrs() fuseops.InodeAttributes {
 }
 
 func (fs *statFS) fileAttrs() fuseops.InodeAttributes {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+
 	return fs.cannedStatResponse
 }