Subject: ssh blocking in ttyout
To: None <current-users@netbsd.org>
From: Andrew D. Isaacson <adisaacs@mtu.edu>
List: current-users
Date: 11/03/1998 12:00:17
System: -current as of about 2 weeks ago, running on a 386sx-16, using
pcvt console.

On a virtual console, I ssh to another host.  It works fine for a
while, but eventually the ssh session "locks up"; it doesn't respond
to anything I type.  Switching to another VC, ps axl reveals:

0 16470 15092   8   4  0   360  816 ttyout I+   v1    0:20.08 ssh gandalf (

At this point, my only choice seems to be to kill the local ssh.  When
I do this, ssh dies, and the shell from which I ran ssh receives all of
the keystrokes I entered after the lockup.  The shell then functions
perfectly well, and I can re-ssh.

I haven't hit control-s, and the scroll lock light is not on.  Neither
control-q nor scroll lock fix the problem.

This seems to happen most often when using full-screen curses or
S-Lang apps on the remote machine; I've seen it with both mutt and
slrn.  Generally the lockup occurs during a screen refresh.

If I write something to the VC by doing an "echo foo > /dev/ttyv1", it
shows up on the "locked" screen.  Nothing else changes.

Any ideas?  Anything I can do to help debug this?

-andy