signal内核是不是有问题,还是我方法不对

void thread1_signal_handler(int sig)
{
    rt_kprintf("signal\r\n");
}
rt_signal_install(SIGUSR1, thread1_signal_handler);
rt_signal_unmask(SIGUSR1);
while(1)
{
    rt_thread_kill(id,SIGUSR1);
    rt_thread_mdelay(1000);
}