Timeout is doubled - socket.create_connection()

Bug report

Bug description:

import socket
import time
start = time.time()
sock = socket.create_connection(
    address=("foobar", 10000),
    timeout=5)
print(time.time() - start)

No matter what value you specify as a timeout, the timeout is always doubled. If you specify 5 seconds, an exception will only be thrown after 10 seconds; if you specify 10 seconds, then only after 20.

Tested on Debian 12 with Python 3.11.

CPython versions tested on:

3.11

Operating systems tested on:

Linux

从 socket.create_connection() 入口点开始，在 Linux 上使用 Python 3.11 重现所提供的脚本，并测量多个 timeout 值下经过的时间。跟踪 timeout 处理流程，并确定相关回归测试的位置。完成的标准是观测到的 timeout 与请求的值一致，并且该行为由测试覆盖。