COM_STMT_SEND_LONG_DATA lead to crash

bt:
(gdb) bt
#0 0x00007f96004896ab in raise () from /lib64/libpthread.so.0
#1 0x00007f96009ed472 in session_store_stmt (session=0x7f95c8012580, buf=0x7f95c8025450, server=0x1accbf0) at /home/xiangzhong.wxd/gitlab/MaxScale/server/core/session.cc:953
#2 0x00007f95fbf7f105 in handle_got_target (inst=0x1af9700, rses=0x7f95c8023640, querybuf=0x7f95c8025450, target=std::tr1::shared_ptr (count 2) 0x7f95c8024360, store=true)
at /home/xiangzhong.wxd/gitlab/MaxScale/server/modules/routing/readwritesplit/rwsplit_route_stmt.cc:1168
#3 0x00007f95fbf7bba4 in route_single_stmt (inst=0x1af9700, rses=0x7f95c8023640, querybuf=0x7f95c8025450, info=...)
at /home/xiangzhong.wxd/gitlab/MaxScale/server/modules/routing/readwritesplit/rwsplit_route_stmt.cc:264
#4 0x00007f95fbf729b9 in routeQuery (instance=0x1af9700, router_session=0x7f95c8023640, querybuf=0x7f95c8025450)
at /home/xiangzhong.wxd/gitlab/MaxScale/server/modules/routing/readwritesplit/readwritesplit.cc:964
#5 0x00007f95fa6b46ba in route_by_statement (session=0x7f95c8012580, capabilities=4294967431, p_readbuf=0x7f95d35fa560)
at /home/xiangzhong.wxd/gitlab/MaxScale/server/modules/protocol/MySQL/mariadbclient/mysql_client.cc:1564
#6 0x00007f95fa6b2d84 in gw_read_finish_processing (dcb=0x7f95c8013e90, read_buffer=0x7f95c80141b0, capabilities=4294967431)
at /home/xiangzhong.wxd/gitlab/MaxScale/server/modules/protocol/MySQL/mariadbclient/mysql_client.cc:1063
#7 0x00007f95fa6b2b25 in gw_read_normal_data (dcb=0x7f95c8013e90, read_buffer=0x7f95c80141b0, nbytes_read=179)
at /home/xiangzhong.wxd/gitlab/MaxScale/server/modules/protocol/MySQL/mariadbclient/mysql_client.cc:1005
#8 0x00007f95fa6b1225 in gw_read_client_event (dcb=0x7f95c8013e90) at /home/xiangzhong.wxd/gitlab/MaxScale/server/modules/protocol/MySQL/mariadbclient/mysql_client.cc:516
#9 0x00007f960099ceb7 in dcb_process_poll_events (dcb=0x7f95c8013e90, events=5) at /home/xiangzhong.wxd/gitlab/MaxScale/server/core/dcb.cc:3145
#10 0x00007f960099d278 in dcb_handler (dcb=0x7f95c8013e90, events=5) at /home/xiangzhong.wxd/gitlab/MaxScale/server/core/dcb.cc:3230
#11 0x00007f960099d335 in dcb_poll_handler (data=0x7f95c8013e90, thread_id=8, events=5) at /home/xiangzhong.wxd/gitlab/MaxScale/server/core/dcb.cc:3266
#12 0x00007f96009fe9f5 in maxscale::Worker::poll_waitevents (this=0x1ac9f70) at /home/xiangzhong.wxd/gitlab/MaxScale/server/core/worker.cc:1205
#13 0x00007f96009fdb88 in maxscale::Worker::run (this=0x1ac9f70) at /home/xiangzhong.wxd/gitlab/MaxScale/server/core/worker.cc:885
#14 0x00007f96009fe60c in maxscale::Worker::thread_main (pArg=0x1ac9f70) at /home/xiangzhong.wxd/gitlab/MaxScale/server/core/worker.cc:1106
#15 0x00007f9600481aa1 in start_thread () from /lib64/libpthread.so.0
#16 0x00007f95fe64c93d in clone () from /lib64/libc.so.6

case :

static int test_long_data(MYSQL *conn, int sqlsize)

{

    int data1size = sqlsize/2;

    char * data1 = (char*) malloc(data1size);

    memset(data1,97,data1size);

    char * data3 = (char*) malloc(sqlsize);

    memset(data3,99,sqlsize);

    //printf("data size:%d, %d\n", sqlsize, sizeof(data1));

    MYSQL_STMT *stmt;

    stmt = mysql_stmt_init(conn);

    int        rc, int_data;

    MYSQL_RES  *result;

    MYSQL_BIND my_bind[1];

    char query[MAX_TEST_QUERY_LENGTH];

    rc= mysql_autocommit(conn, TRUE);

    if(NULL == stmt){

        fprintf(stderr,"%s",mysql_error(conn));

        return 0;

    }

    if (mysql_stmt_prepare(stmt, "select ?", strlen("select ?")) != 0) {

        print_stmt_error(stmt,"stmt prepare fail");

        return 0;

    }

    /* Always bzero all members of bind parameter */

    bzero((char*) my_bind, sizeof(my_bind));

    my_bind[0].buffer= (void *)&int_data;

    my_bind[0].buffer_type= MYSQL_TYPE_STRING;

    if (mysql_stmt_bind_param(stmt, my_bind) != 0) {

        print_stmt_error(stmt,"bind param error");

        return 0;

    }

    /* supply data in pieces */

    if(mysql_stmt_send_long_data(stmt, 0, data1, data1size) != 0){

        print_stmt_error(stmt,"send long data1 failed");

        return 0;

    }

    if(mysql_stmt_send_long_data(stmt, 0, data3, sqlsize) != 0){

        print_stmt_error(stmt, "send long data3 failed");

        return 0;

    }

    /* execute */

    if(mysql_stmt_execute(stmt) != 0){

        print_stmt_error(stmt,"execute prepare stmt failed");

        return 0;

    }

    /* get the result */

    result= mysql_store_result(conn);

    mysql_free_result(result);

    mysql_stmt_close(stmt);

    free(data1);

    free(data3);

    return 1;

}