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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 receipt
Date: Thu, 1 Aug 2019 12:10:12 +0200	[thread overview]
Message-ID: <20190801101012.GA4816@amd> (raw)
In-Reply-To: <20190801092020.GB19329@kroah.com>

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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.
> 
> 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.
> 
> 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
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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  reply	other threads:[~2019-08-01 10:10 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-25 16:11 [PATCH v2 0/7] TTY Keyboard Status Request Arseny Maslennikov
2019-06-25 16:11 ` [PATCH v2 1/7] signal.h: Define SIGINFO on all architectures Arseny Maslennikov
2019-06-25 16:11 ` [PATCH v2 2/7] tty: termios: Reserve space for VSTATUS in .c_cc Arseny Maslennikov
2019-06-25 16:11 ` [PATCH v2 3/7] n_tty: Send SIGINFO to fg pgrp on status request character Arseny Maslennikov
2019-06-25 16:11 ` [PATCH v2 4/7] linux/signal.h: Ignore SIGINFO by default in new tasks Arseny Maslennikov
2019-06-25 21:32   ` Theodore Ts'o
2019-06-26 13:49     ` Arseny Maslennikov
2019-07-29 10:55     ` Arseny Maslennikov
2019-06-25 16:11 ` [PATCH v2 5/7] tty: Add NOKERNINFO lflag to termios Arseny Maslennikov
2019-06-25 16:11 ` [PATCH v2 6/7] n_tty: ->ops->write: Cut core logic out to a separate function Arseny Maslennikov
2019-06-25 16:11 ` [PATCH v2 7/7] n_tty: Provide an informational line on VSTATUS receipt Arseny Maslennikov
2019-07-30 16:19   ` Greg Kroah-Hartman
2019-07-31 22:23     ` Arseny Maslennikov
2019-08-01  9:20       ` Greg Kroah-Hartman
2019-08-01 10:10         ` Pavel Machek [this message]
2019-08-01 12:44         ` Rob Landley
2019-08-02 11:04         ` Arseny Maslennikov
2019-08-01 12:35     ` Rob Landley
2019-07-29 10:56 ` [PATCH v2 0/7] TTY Keyboard Status Request Arseny Maslennikov

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