pid_alive
if (!pid && !pid_alive(tsk))
if (pid_alive(task)) {
if (pid_alive(task)) {
if (pid_alive(start)) {
if (pid_alive(tsk))
if (!nr && !pid_alive(p))
can_cont = pid_alive(g) && pid_alive(t);
if (pid_alive(p))
if (!pid_alive(tsk))
if (!pid_alive(child))