Re: Mosh regression between 10.x and 11-stable

On 2016-Aug-10 14:32:15 -0400, john hood <cgull_at_glup.org> wrote:
>On 8/10/16 4:18 AM, Peter Jeremy wrote:
>> I recently updated one of my VPS hosts from 10.3-RELEASE-p5 to 11.0-BETA4
>> r303811 and mosh to that host from my Linux laptop stopped working.  All
>> I get on the laptop is:
>> $ mosh remotehost
>> Connection to remotehost closed.
>> /usr/bin/mosh: Did not find mosh server startup message.

>> 1) the "MOSH CONNECT" message isn't making it out of the local ssh process.
>
>Do you know if the message is getting out of mosh-server?  into sshd?
>Do you know if mosh-server is actually running?  (It will log utmp
>entries on startup.)

mosh-server is running - I can see it from another session and redirecting
verbose output into a file, I get:
----
mosh-server (mosh 1.2.5) [build mosh 1.2.5]
Copyright 2012 Keith Winstein <mosh-devel_at_mit.edu>
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[mosh-server detached, pid = 4202]

Warning: termios IUTF8 flag not defined.
Character-erase of multibyte character sequence
probably does not work properly on this platform.
----

I can't tell if it's actually writing into the remote ssh process.

>> 2) it's racy because I can get it from "always fails" to "sometimes works".
>
>How do you get it there?

- Add '-v' to the local ssh command.
- ktrace the remote mosh-server process (this seems to make it consistently work).

-- 
Peter Jeremy