问为什么我的Ubuntu在启动python脚本后会死机？

EN

from time import sleep
from threading import Thread, Event
from scapy.all import *

class Sniffer(Thread):
    def __init__(self):
        Thread.__init__(self)
        self.count_downloaded_bytes = 0

    def run(self):
        sniff(filter="ip", prn=self.get_packet)

    def get_packet(self, packet):
        self.count_downloaded_bytes += len(packet) # calculate size of packets

    def get_count_downloaded_bytes(self):
        count_d_bytes = self.count_downloaded_bytes
        self.count_downloaded_bytes = 0
        return count_d_bytes # returns size of downloaded data in bytes

class NetworkSpeed(Thread):
    def  __init__(self):
        Thread.__init__(self)
        self.sniffer = Sniffer() # create seconds thread, that sniffs traffic
        self.start()

    def calculate_bandwidth(self, count_downloaded_bytes, duration):
        download_speed = (count_downloaded_bytes / 1000000 * 8) / duration
        print('download_speed = ', download_speed)

    def run(self):
        counter = 0
        self.sniffer.start()
        while True:
            if counter == 10:
            self.calculate_bandwidth(self.sniffer.get_count_downloaded_bytes(), 10)
            counter = 0

        counter += 1
        sleep(1)

network_speed = NetworkSpeed()