hang on exit bug under Linux

[Nicolas Williams]

 - with no ptys, you want to make sure that your remote command closes
   all its stdio and you get no hang (there was a hang bug wrt
   agent/x11/port forwarding).

 - with pty you may want sshd to do killpg() on the pty/tty process
   groups when the client closes the session.

 - with and without ptys it would be nice to have a client-side option
   to have the client close the main session as soon as possible (launch
   and forget).

Closing a session is a client-side decision (unless the server is
halting/rebooting, say :)

I've made the mistake of thinking otherwise.

Cheers,

Nico


On Mon, Dec 10, 2001 at 09:40:22AM -0800, Michael wrote:
> > 
> > [..]
> > > Like I said, ssh-1.2.27 works fine
> > > OpenSSH_2.9.9p2 is guaranteed to hang
> > >
> > ssh 1.2.27 could/would lose data on scp because is favored quiting
> > before the buffers were flushed.
> > 
> > > This means that a daemon can never be stopped and restarted from the
> > > keyboard without a hang or screwing around with special exit
> > > procedures. Looks, sounds, smells like a bug to me.
> > >
> > 
> > This pretty much is very unhelpful.  If you read the whole history
> > on this mailinglist a more USEFUL insight would be why it occurs on
> > some UNIXes and not others.  And what the correct solution is.
> > 
> > Something no one has been able to do, and I'm at a loss without
> > approving a hack that may bite us in the ass later on.
> > 
> 
> I have been following this thread for some time. John Bowman 
> submitted a patch for 3.01 on Nov 14 that purportedly fixes the 
> problem. I don't know what this does on various OS's and am certainly 
> not the one to say it is "the" permanent fix, but there was no 
> further comment after that. I'd like to see a fix as the present 
> situation certainly is not acceptable in the long run. If John's fix 
> works for Linux and does so without data loss, then perhaps it should 
> be included and compiled in by configuration option for those OS's 
> where it is known to solve the problem.
> 
> Michael
> Michael at Insulin-Pumpers.org
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