Index: head/sys/kern/vfs_mountroot.c
===================================================================
--- head/sys/kern/vfs_mountroot.c
+++ head/sys/kern/vfs_mountroot.c
@@ -263,6 +263,11 @@
 		if (error)
 			return (error);
 
+		error = VFS_STATFS(mp, &mp->mnt_stat);
+		KASSERT(error == 0, ("VFS_STATFS(devfs) failed %d", error));
+		if (error)
+			return (error);
+
 		opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
 		TAILQ_INIT(opts);
 		mp->mnt_opt = opts;