EOFError when threading

[xvalentinex]

When threading multiple SSH sessions Transport.get_exception() will randomly return an EOFError when executing Transport.open_session() on a second Channel.exec_command().

Example:

class Router(Thread):
        tlist = []
        lock = Lock()

        def __init__(self, login):
                Thread.__init__(self)
                self.login = login
                self.ssh = paramiko.SSHClient()
                self.ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())

        def run(self):
                try:
                        self.ssh.connect(timeout=20, **self.login)
                        stdin, stdout, stderr = self.ssh.exec_command('command1')
                        # Do something with stdout
                        stdin, stdout, stderr = self.exec_command('command2')
                        # Radomly raises EOFError on some threads, other threads will work as expected
                finally:
                        self.ssh.close()

if __name__ == '__main__':
        for rtr, login in ROUTERS.items():
                Router.lock.acquire()
                rtr = Router(login)
                Router.tlist.append(rtr)
                rtr.setName(name)
                Router.lock.release()
                rtr.start()
        for rtr in Router.tlist:
                rtr.join()

If I go lower and use SSHClient only for connecting then get_transport, and open_session I will have the same result. However, if I create two channels using open_session before running an exec_command on either, it will work as expected without an EOFError.

Example that works:
tran = self.ssh.get_transport()
chan1 = tran.open_session()
chan2 = tran.open_session()
chan1.exec_command('command1')
# Do something with chan1.makefile
chan2.exec_command('command2')
# Do something with chan2.makefile

Example that will raise random EOFErrors:
tran = self.ssh.get_transport()
chan = tran.open_session()
chan.exec_command('command1')
# Do something with chan.makefile
chan = tran.open_session()
# Raises random EOFErrors

Also if I limit the thread count to 1 using Event() everything works as expected, but if I limit the thread count to anything over 1 I see the random EOFErrors.

I would be happy to provide more details if needed.