diff --git a/fs/namespace.c b/fs/namespace.c
index 2019899f2ab822caec7dd235e8c610096549a93b..e5aa1eeb574825c5e8b63da41291e7e0d96b2fc6 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1526,6 +1526,10 @@ static void chroot_fs_refs(struct nameidata *old_nd, struct nameidata *new_nd)
  * pointed to by put_old must yield the same directory as new_root. No other
  * file system may be mounted on put_old. After all, new_root is a mountpoint.
  *
+ * Also, the current root cannot be on the 'rootfs' (initial ramfs) filesystem.
+ * See Documentation/filesystems/ramfs-rootfs-initramfs.txt for alternatives
+ * in this situation.
+ *
  * Notes:
  *  - we don't move root/cwd if they are not at the root (reason: if something
  *    cared enough to change them, it's probably wrong to force them elsewhere)