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Date:   Thu, 1 Aug 2019 12:10:12 +0200
From:   Pavel Machek <pavel@denx.de>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Arseny Maslennikov <ar@cs.msu.ru>, Jiri Slaby <jslaby@suse.com>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        "Vladimir D. Seleznev" <vseleznv@altlinux.org>,
        Rob Landley <rob@landley.net>,
        "Eric W. Biederman" <ebiederm@xmission.com>
Subject: Re: [PATCH v2 7/7] n_tty: Provide an informational line on VSTATUS
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Message-ID: <20190801101012.GA4816@amd>
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Hi!

> > The use-case for this is different: the ^T-line as proposed by this
> > patch is for the user that interacts with a system through a terminal, =
who
> > wants to be informed not about the whole system (sort of what SysRq-t
> > tells you), but about what they run on that particular tty.
>=20
> Ok, fair enough, although if you just add a new sysrq option for "what
> is running on this tty", would that help resolve this?

This is meant for unpriviledged users, unlike sysrq.

> > This is much less about "why does my system/kernel seem to hang?" or
> > exposing low-level internals (registers, hrtimers, locks, ...), and more
> > about "is my SSH terminal session unresponsive?" and "I ran a command,
> > it doesn't finish, how's it doing?".
> > e.g. A user might want to know if their SSH connection is alive without
> > interrupting anything, while having no access both to SysRq and console,
> > and no one in fg pgrp actually handles SIGINFO.
>=20
> If you have access to a tty, you should have access to sysrq, right?

No. This is supposed to work over ssh. SysRq is not supposed to work
over ssh; that would be a security hole.

Best regards,
									Pavel
--=20
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo=
g.html

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