diff --git a/include/mux.h b/include/mux.h
index c43ce79..b8d242c 100644
--- a/include/mux.h
+++ b/include/mux.h
@@ -22,7 +22,7 @@
 	void *aux;	/* for private use by client */
 
 /* private */
-	QLock lk;
+	QLock lk;	/* must be first for muxinit */
 	QLock inlk;
 	QLock outlk;
 	Rendez tagrend;