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

From: Jiri Slaby
Date: Thu Jan 26 2012 - 08:15:44 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.

thanks,
--
js
suse labs
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