task_call_func
extern int task_call_func(struct task_struct *p, task_call_f func, void *arg);
return task_call_func(p, __set_task_frozen, NULL);
if (frozen(p) && !task_call_func(p, __restore_freezer_state, NULL))
ret = task_call_func(task, klp_check_and_switch_task, &old_name);
if (task_call_func(t, check_slow_task, &rscr))