/***************************************************************************** 
* 
* File Name : main.c
* 
* Description: main 
* 
* Copyright (c) 2014 Winner Micro Electronic Design Co., Ltd. 
* All rights reserved. 
* 
* Author : dave
* 
* Date : 2014-6-14
*****************************************************************************/ 
#include "wm_include.h"
static OS_STK TaskStk1[512];
static OS_STK TaskStk2[512];
static void user_task1(void)
{
    while(1)
    {
        printf("---> %s\r\n",__func__);
        tls_os_time_delay(HZ);
    }
}
static void user_task2(void)
{
    while(1)
    {
        printf("---> %s\r\n",__func__);
        tls_os_time_delay(HZ);
    }
}
void UserMain(void)
{
    printf("\n user task \n");
    tls_os_task_create(NULL, "task1",
                        ( void (*))user_task1,
                        NULL,
                        (void *)TaskStk1,          /* task's stack start address */
                        sizeof(TaskStk1), /* task's stack size, unit:byte */
                        31,
                        0);
    tls_os_task_create(NULL, "task2",
                        ( void (*))user_task2,
                        NULL,
                        (void *)TaskStk2,          /* task's stack start address */
                        sizeof(TaskStk2), /* task's stack size, unit:byte */
                        32,
                        0);
#if DEMO_CONSOLE
    CreateDemoTask();
#endif
//用户自己的task
}

问题已解决,和任务栈的大小有关,