create thread的时候发生core dump

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>
#define THREAD_COUNT 12

void show_thread_policy(int threadno){
        int policy;
        struct sched_param param;
        pthread_getschedparam(pthread_self(), &policy, &param);
        switch(policy){
        case SCHED_OTHER:
                printf("SCHED_OTHER %d
", threadno);
                break;
        case SCHED_RR:
                printf("SCHED_RR %d
", threadno);
                break;
        case SCHED_FIFO:
                printf("SCHED_FIFO %d
", threadno);
                break;
        default:
                printf("UNKNOWN
");
        }
}

void *thread(void *arg){
        int i,j;
        long threadno = (long)arg;
        printf("thread %d start 
", threadno);
        printf("thread ------------------------------0
");
        sleep(1);
        printf("---------1---------------
");
        show_thread_policy(threadno);
        printf("---------2---------------
");
        for(int i=0;i<10;i++){
                printf("---------3---------------
");
                for(j=0;j<10000000;j++){

                }

                printf("thread %d
", threadno);
        }

        printf("thread %d exit
", threadno);
        return NULL;
}

int main(int argc, char *argv[]){
        long i;
        pthread_attr_t attr[THREAD_COUNT];
        pthread_t pth[THREAD_COUNT];
        struct sched_param param;
        for(i=0;i<THREAD_COUNT;++i){
                pthread_attr_init(&attr[i]);
                for(i=0;i<THREAD_COUNT/2;++i){
                        param.sched_priority = 10;
                        pthread_attr_setschedpolicy(&attr[i], SCHED_FIFO);
                        pthread_attr_setschedparam(&attr[i], &param);
                        pthread_attr_setinheritsched(&attr[i], PTHREAD_EXPLICIT_SCHED);
                }

                for(i=THREAD_COUNT/2;i<THREAD_COUNT;++i){
                        param.sched_priority = 20;
                        pthread_attr_setschedpolicy(&attr[i], SCHED_FIFO);
                        pthread_attr_setschedparam(&attr[i], &param);
                        pthread_attr_setinheritsched(&attr[i], PTHREAD_EXPLICIT_SCHED);
                }

                for(i=0;i<THREAD_COUNT;++i){
                        pthread_create(&pth[i], &attr[i], thread, (void *)i);
                        printf("--------------------create thread %d------------
", i);
                }

                for(i=0;i<THREAD_COUNT;++i){
                        pthread_join(pth[i], NULL);
                }

                for(i=0;i<THREAD_COUNT;++i){
                        pthread_attr_destroy(&attr[i]);
                }

                return 0;
        }
}

编译之后执行的结果如下：

[root@Alston C++]# ./thread_2.exe
thread 0 start
thread ------------------------------0
--------------------create thread 0------------
--------------------create thread 1------------
--------------------create thread 2------------
--------------------create thread 3------------
Segmentation fault (core dumped)

目前还没调查出来原因。