线程中调用rt_thread_mdelay（）函数卡死

int main(void)
{    
    interrupt_config();
    gd_eval_led_init(LED1);
        ledTaskInit();
    while(1)
        {
            rt_kprintf("running...");    
    }
}
void led_thread_entry(void *p)
{
    while(1)
    {
        gd_eval_led_toggle(LED1);
        rt_thread_mdelay(500);
    }
}
void ledTaskInit(void)
{
        ledThread = rt_thread_create("ledThread",
                                                                    led_thread_entry,
                                                                    RT_NULL,
                                                                    512,
                                                                    10,
                                                                    10
                                                                );
    if(ledThread != RT_NULL)
        rt_thread_startup(ledThread);
}