Index: sys/kern/vfs_mountroot.c
===================================================================
--- sys/kern/vfs_mountroot.c
+++ sys/kern/vfs_mountroot.c
@@ -580,6 +580,7 @@
 	int error, fd, len;
 
 	td = curthread;
+	fd = -1;
 
 	error = parse_token(conf, &tok);
 	if (error)
@@ -635,9 +636,15 @@
 	root_mount_mddev = mdio->md_unit;
 	printf(MD_NAME "%u attached to %s\n", root_mount_mddev, mdio->md_file);
 
-	error = kern_close(td, fd);
-
  out:
+	if (fd >= 0) {
+		int cerror;
+
+		/* Don't leak the fd, but preserve earlier errors. */
+		cerror = kern_close(td, fd);
+		if (error == 0)
+			error = cerror;
+	}
 	free(mdio, M_TEMP);
 	return (error);
 }