hang on exit bug under Linux

Frank Cusack fcusack at fcusack.com
Fri Feb 22 08:07:08 EST 2002

On Thu, Feb 21, 2002 at 12:05:06PM -0800, Frank Cusack wrote:
> On Thu, Feb 21, 2002 at 11:34:06AM -0800, Michael wrote:
> > Just thought I'd mention that when you restart "init"
> > 
> > kill -HUP 1
> > 
> > ssh 3.02p1 hangs as expected. What data would I expect back from 
> > that??
> I don't see that behaviour.  I assume you are talking about an sshd
> patched with the "AllowDataLossOnPty" patch.
>     ssh localhost -t "sleep 20 & exit"
> returns immediately before and after 'kill -HUP 1'.  Perhaps you aren't
> requesting a pty in your test?

Feeling that I might have misread the message, I tried other things also,
like ssh root at localhost -t "kill -HUP 1 & exit" which also returns

I did find something very interesting, 'ssh localhost -t "sleep 20 & exit"'
always returns immediately, even on an unpatched sshd.  It's only when
I do a plain "ssh localhost" and then run "sleep 20 & exit" interactively,
do I see any effect from the patch.  I would have sworn I had seen hangs
when using the first form, but I am unable to reproduce it.


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