From b562b0fbc4b0169871db7f13516541e225a96735 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Mon, 21 Nov 2016 03:10:41 +0000
Subject: [PATCH] artiq_devtool: detect a race condition during connect.

---
 artiq/frontend/artiq_devtool.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/artiq/frontend/artiq_devtool.py b/artiq/frontend/artiq_devtool.py
index 7d4d71f5a..fc6f58048 100644
--- a/artiq/frontend/artiq_devtool.py
+++ b/artiq/frontend/artiq_devtool.py
@@ -116,6 +116,10 @@ def main():
                     local_stream, peer_addr = listener.accept()
                     logger.info("Accepting %s:%s and opening SSH channel to %s:%s",
                                 *peer_addr, args.ip, port)
+                    if get_ssh().get_transport() is None:
+                        logger.error("Trying to open a channel before the transport is ready!")
+                        continue
+
                     remote_stream = get_ssh().get_transport() \
                         .open_channel('direct-tcpip', (args.ip, port), peer_addr)
                     while True: