From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73ABCC2D0C3 for ; Mon, 30 Dec 2019 05:49:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 510D820663 for ; Mon, 30 Dec 2019 05:49:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727234AbfL3Ft3 (ORCPT ); Mon, 30 Dec 2019 00:49:29 -0500 Received: from mout-p-202.mailbox.org ([80.241.56.172]:36948 "EHLO mout-p-202.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727069AbfL3Ft3 (ORCPT ); Mon, 30 Dec 2019 00:49:29 -0500 Received: from smtp1.mailbox.org (smtp1.mailbox.org [80.241.60.240]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mout-p-202.mailbox.org (Postfix) with ESMTPS id 47mRMV2kFdzQlB0; Mon, 30 Dec 2019 06:49:26 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp1.mailbox.org ([80.241.60.240]) by spamfilter06.heinlein-hosting.de (spamfilter06.heinlein-hosting.de [80.241.56.125]) (amavisd-new, port 10030) with ESMTP id Osl2T2x5pLfL; Mon, 30 Dec 2019 06:49:22 +0100 (CET) Date: Mon, 30 Dec 2019 16:49:13 +1100 From: Aleksa Sarai To: Al Viro Cc: David Howells , Eric Biederman , Linus Torvalds , stable@vger.kernel.org, Christian Brauner , Serge Hallyn , dev@opencontainers.org, containers@lists.linux-foundation.org, linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 0/1] mount: universally disallow mounting over symlinks Message-ID: <20191230054913.c5avdjqbygtur2l7@yavin.dot.cyphar.com> References: <20191230052036.8765-1-cyphar@cyphar.com> <20191230054413.GX4203@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="vstjrid4bmeb3iov" Content-Disposition: inline In-Reply-To: <20191230054413.GX4203@ZenIV.linux.org.uk> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --vstjrid4bmeb3iov Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2019-12-30, Al Viro wrote: > On Mon, Dec 30, 2019 at 04:20:35PM +1100, Aleksa Sarai wrote: >=20 > > A reasonably detailed explanation of the issues is provided in the patch > > itself, but the full traces produced by both the oopses and deadlocks is > > included below (it makes little sense to include them in the commit sin= ce we > > are disabling this feature, not directly fixing the bugs themselves). > >=20 > > I've posted this as an RFC on whether this feature should be allowed at > > all (and if anyone knows of legitimate uses for it), or if we should > > work on fixing these other kernel bugs that it exposes. >=20 > Umm... Are all of those traces > a) reproducible on mainline and This was on viro/for-next, I'll retry it on v5.5-rc4. > b) reproducible as the first oopsen? The NULL and garbage pointer derefs are reproducible as the first oops. Looking at my logs, it looks like the deadlocks were always triggered after the oops, but that might just have been a mistake on my part while testing things. > As it is, quite a few might be secondary results of earlier memory > corruption... Yeah, I thought that might be the case but decided to include them anyway (the /proc/self/stack RCU stall is definitely the result of other corruption and stalls). --=20 Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH --vstjrid4bmeb3iov Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQSxZm6dtfE8gxLLfYqdlLljIbnQEgUCXgmP1gAKCRCdlLljIbnQ En8yAP4heusqckPwVD1E6oISJdz6Un9hh96337R1CzO+HkhhwgEAwXuurrT9WDJY vzW4vyGjAMtEZpNg3y1cdnODYnBG6Qs= =FWL9 -----END PGP SIGNATURE----- --vstjrid4bmeb3iov--