在什么情况下RT-Thread线程会不见呢

用ps命令，一开始是这样

然后是这样

env_recv不见了

线程初始化函数

result1 = rt_thread_init(&env_send_thread,

"env_send",

                        env_send,

                        RT_NULL,

                        &env_send_stack[0],

                        sizeof(env_send_stack),

                        19,

                        50);

if (result1 == RT_EOK) 

{

    rt_thread_startup(&env_send_thread);

}

//接收线程

result2 = rt_thread_init(&env_recv_thread,

                        "env_recv",

                        env_recv,

                        RT_NULL,

                        &env_recv_stack[0],

                        sizeof(env_recv_stack),

                        18,

                        50);

if (result2 == RT_EOK) 

{

    rt_thread_startup(&env_recv_thread);

}

result = rt_thread_init(&sc_read_thread,

"LCD_R",

                        screen_process,

                        RT_NULL,

                        &sc_read_stack[0],

                        sizeof(sc_read_stack),

                        19,

                        50);

if (result == RT_EOK) {

    rt_thread_startup(&sc_read_thread);

}

else

{

    return RT_ERROR;

}

result = rt_thread_init(&sc_fresh_thread,

                        "LCD_F",

                        screen_fresh,

                        RT_NULL,

                        &sc_fresh_stack[0],

                        sizeof(sc_fresh_stack),

                        19,

                        50);

if (result == RT_EOK)

    rt_thread_startup(&sc_fresh_thread);

else

{

    return RT_ERROR;

}