From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1751494AbcLCTLT (ORCPT <rfc822;w@1wt.eu>);
        Sat, 3 Dec 2016 14:11:19 -0500
Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:53036 "EHLO
        atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S1750749AbcLCTLR (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Sat, 3 Dec 2016 14:11:17 -0500
Date: Sat, 3 Dec 2016 20:11:13 +0100
From: Pavel Machek <pavel@ucw.cz>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzkaller <syzkaller@googlegroups.com>,
        Oleg Nesterov <oleg@redhat.com>, Denys Vlasenko <dvlasenk@redhat.com>,
        jan.kratochvil@redhat.com, palves@redhat.com,
        Roland McGrath <roland@hack.frob.com>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: Unkillable processes due to PTRACE_TRACEME again
Message-ID: <20161203191113.GA13417@amd>
References: <CACT4Y+ZnT3ngSvbs=U8=41TAMpaS8YqbVb7KdiK9QTM7Jd+JgA@mail.gmail.com>
 <20161202210217.GA15126@amd>
 <CACT4Y+YUnM1kAZo6orq2oqjAvuYF6z47yZ5gjrKzT4gmQ7fktg@mail.gmail.com>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha1;
        protocol="application/pgp-signature"; boundary="zhXaljGHf11kAtnf"
Content-Disposition: inline
In-Reply-To: <CACT4Y+YUnM1kAZo6orq2oqjAvuYF6z47yZ5gjrKzT4gmQ7fktg@mail.gmail.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org


--zhXaljGHf11kAtnf
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

Hi!

You cc-ed me on initial mail, I replied, and you removed me from cc. Ouch.

On Sat 2016-12-03 16:55:49, Dmitry Vyukov wrote:
> On Fri, Dec 2, 2016 at 10:02 PM, Pavel Machek <pavel@ucw.cz> wrote:
> > On Fri 2016-12-02 19:48:40, Dmitry Vyukov wrote:
> >> Hello,
> >>
> >> There was an issue discussed a year ago which leads to
> >> unkillalble/unwaitable zombie processes due to PTRACE_TRACEME:
> >> https://groups.google.com/d/msg/syzkaller/uGzwvhlCXAw/E-cfY2ejAgAJ
> >> and I though it has been fixed by "wait/ptrace: assume __WALL if the
> >> child is traced":
> >> https://groups.google.com/d/msg/syzkaller/caeB1ebZWAs/gcbvcM2HDAAJ
> >>
> >> I am not on 2caceb3294a78c389b462e7e236a4e744a53a474 (Dec 1). And see
> >
> > "Now on"?
>=20
> Yes.
>=20
> >> the same unwaitable zombie processes.
> >
> > Well.. I guess git bisect is one option...?
>=20
> I've checked on:
>=20
> commit 91c4e8ea8f05916df0c8a6f383508ac7c9e10dba
> Author: Oleg Nesterov <oleg@redhat.com>
> Date:   Mon May 23 16:23:53 2016 -0700
>     wait: allow sys_waitid() to accept __WNOTHREAD/__WCLONE/__WALL
>=20
> and the program hangs the same way. So it seems that it was just never fi=
xed.

Ouch #2. Oleg, any ideas?

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

--zhXaljGHf11kAtnf
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: Digital signature

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1

iEYEARECAAYFAlhDGNEACgkQMOfwapXb+vI/5ACfeImBYeNCT1VVRmhtwKSEgRYY
V0EAnjb2m97BTdd3UCvQm2KM0sMmd6LK
=R3aM
-----END PGP SIGNATURE-----

--zhXaljGHf11kAtnf--