CHILD2
cg_id[PARENT], cg_id[CHILD1], cg_id[CHILD2]);
cg_id[CHILD1], cg_id[CHILD2], cg_id[PARENT]);
cg_id[CHILD2]);
err = join_cgroup(cg_path[CHILD2]);
PROLOGUE "%8llu\n" EPILOGUE, cg_id[CHILD2]);
read_from_cgroup_iter(skel->progs.cgroup_id_printer, cg_fd[CHILD2],