求问一个 python3 的 gevent。 monkey.patch_ssl() 之后运行代码会出错的问题

先上代码

import requests
import gevent
from gevent.pool import Pool
from gevent import monkey
# monkey.patch_all()
monkey.patch_socket()
monkey.patch_ssl()


contents = []
pool = Pool(20)

def req(url):
    res = requests.get(url)
    contents.append(res.status_code)
urls = [
    "http://www.baidu.com",
    "http://www.iplaysoft.com",
    "http://www.cupfox.com",
    "http://www.opbear.com",
    "http://www.bing.ren"
]

gtasks = [pool.spawn(req, url) for url in urls]
gevent.joinall(gtasks)
print(contents)

就这段代码用的是最简单的 gevent 协程请求 requests 如果只用 monkey.patch_socket()是完全没有问题的但凡加上了 monkey.patch_ssl()就会报错或者加上 monkey.patch_all()也会报错

Traceback (most recent call last):
File "/usr/local/python3.6/lib/python3.6/site-packages/gevent/greenlet.py", line 536, in run
result = self._run(*self.args, **self.kwargs)
File "test.py", line 14, in req
res = requests.get(url)
File "/usr/local/python3.6/lib/python3.6/site-packages/requests/api.py", line 72, in get
return request('get', url, params=params, **kwargs)
File "/usr/local/python3.6/lib/python3.6/ssl.py", line 459, in options
super(SSLContext, SSLContext).options.set(self, value)
[Previous line repeated 316 more times]

 RecursionError: maximum recursion depth exceeded while calling a Python object`
 During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/usr/local/python3.6/lib/python3.6/site-packages/gevent/hub.py", line 866, in switch
switch(value)
File "/usr/local/python3.6/lib/python3.6/site-packages/gevent/_tblib.py", line 425, in dump_traceback
return dumps(tb)

Tue Sep 19 10:28:11 2017 <built-in method switch of Greenlet object at 0x10c6c4f20> failed with RecursionError<br/>

Traceback (most recent call last):
File "test.py", line 25, in <module>
gevent.joinall(gtasks)
File "/usr/local/python3.6/lib/python3.6/site-packages/gevent/greenlet.py", line 649, in joinall
return wait(greenlets, timeout=timeout, count=count)
File "/usr/local/python3.6/lib/python3.6/site-packages/gevent/hub.py", line 1037, in wait
return list(iwait(objects, timeout, count))

gevent.hub.LoopExit: ('This operation would block forever',<Hub at 0x10c6c4af8 select default pending=0 ref=0 resolver=<gevent.resolver_thread.Resolver at 0x10c7905f8 pool=<ThreadPool at 0x10c790668 0/2/10>> threadpool=<ThreadPool at 0x10c790668 0/2/10>>)

今天的错误代码长这样。因为错误代码很长很乱我就删掉了中间的一些过程把头尾都留下来了。 gevent 版本 1.2.2 requests 版本 2.18.4

有没有大大帮忙解释下出现错误的原因以及 monkey.patch_ssl()所做的事情