diff --git a/sys/dev/fdc/fdc.c b/sys/dev/fdc/fdc.c
index c0fd5a235b38..d9012500a9df 100644
--- a/sys/dev/fdc/fdc.c
+++ b/sys/dev/fdc/fdc.c
@@ -1101,10 +1101,14 @@ fd_attach(device_t dev)
 	int	typemynor;
 	int	typesize;
 #endif
+	static int cdevsw_add_done = 0;
 
 	fd = device_get_softc(dev);
 
-	cdevsw_add(&fd_cdevsw);	/* XXX */
+	if (!cdevsw_add_done) {
+	    cdevsw_add(&fd_cdevsw);	/* XXX */
+	    cdevsw_add_done++;
+	}
 	make_dev(&fd_cdevsw, (fd->fdu << 6),
 		UID_ROOT, GID_OPERATOR, 0640, "rfd%d", fd->fdu);
 
diff --git a/sys/isa/fd.c b/sys/isa/fd.c
index c0fd5a235b38..d9012500a9df 100644
--- a/sys/isa/fd.c
+++ b/sys/isa/fd.c
@@ -1101,10 +1101,14 @@ fd_attach(device_t dev)
 	int	typemynor;
 	int	typesize;
 #endif
+	static int cdevsw_add_done = 0;
 
 	fd = device_get_softc(dev);
 
-	cdevsw_add(&fd_cdevsw);	/* XXX */
+	if (!cdevsw_add_done) {
+	    cdevsw_add(&fd_cdevsw);	/* XXX */
+	    cdevsw_add_done++;
+	}
 	make_dev(&fd_cdevsw, (fd->fdu << 6),
 		UID_ROOT, GID_OPERATOR, 0640, "rfd%d", fd->fdu);