get_userns_fd
fd_userns1 = get_userns_fd(0, 0, 10000);
fd_userns2 = get_userns_fd(0, 1234, 10000);
extern int get_userns_fd(unsigned long nsid, unsigned long hostid,
attr.userns_fd = get_userns_fd(0, 10000, 10000);
attr.userns_fd = get_userns_fd(0, 10000, 10000);
attr.userns_fd = get_userns_fd(0, 10000, 10000);
attr.userns_fd = get_userns_fd(0, 10000, 10000);
attr.userns_fd = get_userns_fd(0, 10000, 10000);
attr.userns_fd = get_userns_fd(0, 20000, 10000);
attr.userns_fd = get_userns_fd(0, 10000, 10000);
userns_fd = get_userns_fd(0, orig_uid, 10);
userns_fd = get_userns_fd(0, orig_uid, 10);
userns_fd = get_userns_fd(0, orig_uid, 1);
userns_fd = get_userns_fd(0, 0, 1);
userns_fd = get_userns_fd(0, orig_uid, 100);
userns_fd = get_userns_fd(0, orig_uid, 10);
userns_fd = get_userns_fd(0, orig_uid, 10);
userns_fd = get_userns_fd(0, (depth == 0) ? orig_uid : 0, 1);
userns_fd = get_userns_fd(0, getuid(), 1);