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[209.132.180.67]) by mx.google.com with ESMTP id a25si35812319pfk.201.2019.08.01.03.11.02; Thu, 01 Aug 2019 03:11:18 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727854AbfHAKKR (ORCPT + 99 others); Thu, 1 Aug 2019 06:10:17 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:38401 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725379AbfHAKKQ (ORCPT ); Thu, 1 Aug 2019 06:10:16 -0400 Received: by atrey.karlin.mff.cuni.cz (Postfix, from userid 512) id F157E802DA; Thu, 1 Aug 2019 12:10:00 +0200 (CEST) Date: Thu, 1 Aug 2019 12:10:12 +0200 From: Pavel Machek To: Greg Kroah-Hartman Cc: Arseny Maslennikov , Jiri Slaby , Ingo Molnar , Peter Zijlstra , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, "Vladimir D. Seleznev" , Rob Landley , "Eric W. Biederman" Subject: Re: [PATCH v2 7/7] n_tty: Provide an informational line on VSTATUS receipt Message-ID: <20190801101012.GA4816@amd> References: <20190625161153.29811-1-ar@cs.msu.ru> <20190625161153.29811-8-ar@cs.msu.ru> <20190730161940.GA15798@kroah.com> <20190731222359.GA20574@cello> <20190801092020.GB19329@kroah.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="LZvS9be/3tNcYl/X" Content-Disposition: inline In-Reply-To: <20190801092020.GB19329@kroah.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --LZvS9be/3tNcYl/X Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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 --LZvS9be/3tNcYl/X Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl1CuoQACgkQMOfwapXb+vK3gQCfcVYhklm354XQ/g8no7Y8CTU6 zdsAn0kzH5QdUuT6Ax/Vz6mumSrD+H+n =xg6J -----END PGP SIGNATURE----- --LZvS9be/3tNcYl/X--