On Mon, Dec 04, 2023 at 08:52:26AM +0100, Thomas Weißschuh wrote: > @@ -231,7 +231,8 @@ static int insert_header(struct ctl_dir *dir, struct ctl_table_header *header) > return -EROFS; > > /* Am I creating a permanently empty directory? */ > - if (sysctl_is_perm_empty_ctl_header(header)) { > + if (header->ctl_table == sysctl_mount_point || > + sysctl_is_perm_empty_ctl_header(header)) { > if (!RB_EMPTY_ROOT(&dir->root)) > return -EINVAL; > sysctl_set_perm_empty_ctl_header(dir_h); While you're at it. This just made me cringe, and curious if some other changes could be done to make this obviously clear during patch review that this is safe. Luis