用tcp创建HTTP服务器时创建多进程会报错：列表超出索引范围

import socket
import re
import multiprocessing


def service_client(n_s):
    """为这个客户端返回数据"""

    # 1. 接受浏览器发送过来的请求，即http请求
    # GET / HTTP/1.1
    # ...
    request = n_s.recv(1024).decode("utf-8")
    # print('>>>' * 50)
    # print(request)

    request_lines = request.splitlines()
    print('')
    print('>'*50)
    print(request_lines)

    # GET /index.html HTTP/1.1
    file_name = ''
    ret = re.match(r"[^/]+(/[^ ]*)", request_lines[0])
    if ret:
        file_name = ret.group(1)
        # print('-'*50, file_name)
        if file_name == '/':
            file_name = '/index.html'

    # 2. 返回http格式的数据
    try:
        f = open("./html" + file_name, "rb")
    except:
        response = "HTTP/1.1 404 NOT FOUND\r\n"
        response += "\r\n"
        response += '<h1>---file not found---</h1>'
        n_s.send(response.encode('utf-8'))
    else:
        html_content = f.read()
        f.close()
        # 2.1 准备发送给浏览器的数据---header
        response = "HTTP/1.1 200 OK\r\n"
        response += "\r\n"
        # 2.2 ---body
        # response += "<h1>hahaha</h1>"
        # 将response header发送给浏览器
        n_s.send(response.encode("utf-8"))
        # 将response body发送给浏览器
        n_s.send(html_content)

    # 关闭套接字
    n_s.close()


def main():
    # 1.创建套接字
    tcp_serv_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    tcp_serv_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    # 2. 绑定
    tcp_serv_socket.bind(('192.168.1.56', 6648))
    # 3. 监听
    tcp_serv_socket.listen(128)

    while True:

        # 4. 等待连接
        new_socket, client_addr = tcp_serv_socket.accept()
        # 5. 为客户端服务
        # p = multiprocessing.Process(target=service_client, args=(new_socket,))
        # p.start()
        # new_socket.close()
        service_client(new_socket)

    # 6. 关闭套接字
    tcp_serv_socket.close()


if __name__ == '__main__':
    main()

在不添加进程时用上述代码打开网页，程序不报错；
当在第69行添加进程后，把service_client(new_socket)注释掉，运行，打开网页出现错误：
File "C:\Users\lenovo\Desktop\asd_8\http_server.py", line 23, in service_client
ret = re.match(r"[^/]+(/[^ ]*)", request_lines[0])
IndexError: list index out of range

但此时服务器依然可以运行，网页依然可以阅读。
有大佬解释一下这是什么情况吗？

浏览器为火狐，新版Microsoft Edge，相同操作下都可运行，火狐报错，edge正常

https://blog.csdn.net/qq_40942329/article/details/78823432