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Date: Fri, 13 Mar 2020 12:03:39 +0900
To: cygwin AT cygwin DOT com
Subject: Re: gnu screen crashes on ssh disconnect
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From: Takashi Yano via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Takashi Yano <takashi DOT yano AT nifty DOT ne DOT jp>
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On Thu, 12 Mar 2020 19:01:41 -0700
Wayne Davison wrote:
> In recent Cygwin versions I've had gnu screen crash if the parent ssh
> connection closes before an explicit disconnect is performed. If an
> orderly screen disconnect happens first, future closed connections
> (after reconnecting to the screen session) no longer crash screen.
> 
> To reproduce:
> 
> I ssh into my Windows 10 host, move my .screenrc file out of the way
> (to keep the config the default) and run "screen" to start up a basic
> screen session. I then use the ssh close-connection key sequence
> (Enter, tilde, period) to close the connection. When I log back in,
> the ps command shows that screen is already dead and "screen -ls"
> shows a dead screen to clean up using "screen -wipe". If I start a
> fresh screen and use screen's Ctrl+A d key sequence to detach, I can
> use "screen -r" to reconnect and from this point on a lost connection
> no longer makes screen crash, even on future reconnects.
> 
> I haven't seen this crash on Ubuntu, but since it isn't on the same
> version, I tried compiling 4.8.0 to see if that might make it crash --
> it did not. I then compiled the source on Cygwin (without any
> configure options) and that version has the bug, so I guess that this
> is either a Cygwin issue or something weird in my Windows setup.
> 
> Is anyone else seeing this crash?
> 
> I'm attaching a cygcheck.out file that has a couple secrets elided.
> I'll note that I just started to run with disable_pcon set, but it's
> been crashing with and without that.

Thanks for the report. This seems to be a problem related to pseudo
console. I will submit a patch for this issue shortly.

-- 
Takashi Yano <takashi DOT yano AT nifty DOT ne DOT jp>
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