Re: Some programs (vi, ssh) crash when screen buffer height is big

[Sous Lesquels <a9f54d2@gmail.com>]

--- Prelude

I don't think this message will thread correctly. This is a reply to
this message:

https://cygwin.com/ml/cygwin/2014-07/msg00191.html

Message-ID: <20140717082423.GB15332@calimero.vinschen.de>

I unsubscribed from the list in order not to get emails for the whole
list (most of which I'm not interested in, as I'm a Cygwin user
primarily, not a developer), so I don't have the original message to
reply to. Gmail doesn't allow setting In-Reply-To or References
header. I tried what was suggested here:

https://cygwin.com/ml/cygwin/2014-07/msg00222.html

but this replied to cygwin-help@cygwin.com and was auto-bounced. If
anyone has ideas how to thread this properly using clients that do not
support adding user headers (Gmail Web interface for example), without
having the original message to reply to, let me know, so I use that in
the future.

--- The actual message

Thanks Corinna. I initially thought this was an installation issue
and, after this continued to happen and nobody else could reproduce, I
conceded to what you suggested, it's possibly a BLODA thing.

However, just had a completely fresh Win7 and Cygwin install, with
these versions:

cygwin               2.2.1-1            OK
vim                  7.4.808-1          OK

CYGWIN_NT-6.1 2.2.1(0.289/5/3) 2015-08-20 11:42 x86_64 Cygwin

Aside from a few apps (such as Chrome, but nothing "invasive" such as
antivirus or so), it does not have anything that a regular Win7
machine would not have, so I don't think BLODA can be considered as a
cause here.

I tested it by running the script I provided before, i.e.:

#!/bin/bash
for i in {1..123}; do
  echo -e "\033[5A\033[50C\033[0;35mhello\033[0m"
  head -n1000 /var/log/setup.log
done
vi /var/log/setup.log

I can reproduce it often. Not always, but I would say if you cannot
reproduce it with the above script and the below details 1 in 3 times,
I would be very surprised.

From my limited testing:

- It's imperative that the buffer size is big - 9999 is the best
choice - and also the window size. I have mine with Screen Buffer Size
208w 9999h and Window Size 208w 69h, font Lucida Console 14pt
- I could not reproduce in Cygwin terminal (i.e. mintty, as per the
desktop shortcut Cygwin creates), only in cmd (which is the default
when running Cygwin.bat) and ConEmu
(https://github.com/Maximus5/ConEmu)
- The behavior seems different in cmd and ConEmu. When in plain cmd,
cmd crashes and leaves vim process in behind using one core. ConEmu
kills both
- It looks like the file being head-ed above (/var/log/setup.log in my
example) needs to have long lines. Using a big binary dll file
(something from c:/windows/system32) doesn't seem to cause it

Since, when started from cmd, vim continues to run, I did a strace on
vi and pasted it partially here (sorry, cannot post all), hope I did
not miss anything that's important.

http://pastie.org/10364022

Looks like it goes into some loop (the last part of strace just loops
over and over).

Cmd (or bash?) itself crashes with the usual dialog that windows shows
when the app crashes - the text is the usual "Console Window Host has
stopped working". No coredump is produced.

If you need me to test anything else or more information, let me know,
if not sensitive I should be able to provide.

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