Re: Why are not processes HUPped when they open /dev/console?

From: Pavel Machek
Date: Mon Feb 06 2012 - 14:24:08 EST


> On 01/25/2012 10:45 PM, Alan Cox wrote:
> > On Wed, 25 Jan 2012 22:38:40 +0100
> > Jiri Slaby <jslaby@xxxxxxx> wrote:
> >
> >> Hello,
> >>
> >> don't you remember by a chance the reason for this test in __tty_hangup:
> >> if (filp->f_op->write != tty_write)
> >>
> >> The logic there is not to HUP processes that have this tty open via
> >> /dev/console.
> >
> > Because if you hang up the console the machine crashes ?
> >
> > At least that's what used to happen.
>
> It does not crash anymore. However the system (systemd more precisely)
> is confused a bit (well, a huge). So I suppose the test has its meaning.
>
> The whole exercise was about how to fix the userspace issue introduced
> by the added infinite timeout.

> I think the proper solution here is just not to call vhangup in
> userspace for the device which is /dev/console. It never worked anyway.
> Because the HUP signal was never sent and it always timed out.

Perhaps the "infinite timeout" should be reverted, then? It sounds
like a regression...



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