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 23B47C17447 for ; Wed, 13 Nov 2019 07:48:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0509F22459 for ; Wed, 13 Nov 2019 07:48:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726422AbfKMHsf (ORCPT ); Wed, 13 Nov 2019 02:48:35 -0500 Received: from mout-p-201.mailbox.org ([80.241.56.171]:42266 "EHLO mout-p-201.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726107AbfKMHsf (ORCPT ); Wed, 13 Nov 2019 02:48:35 -0500 Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:105:465:1:2:0]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 47CcDY3vdYzQlBb; Wed, 13 Nov 2019 08:48:29 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp2.mailbox.org ([80.241.60.241]) by spamfilter05.heinlein-hosting.de (spamfilter05.heinlein-hosting.de [80.241.56.123]) (amavisd-new, port 10030) with ESMTP id 3hMGDl1msr0T; Wed, 13 Nov 2019 08:48:23 +0100 (CET) Date: Wed, 13 Nov 2019 18:47:57 +1100 From: Aleksa Sarai To: Al Viro Cc: Jeff Layton , "J. Bruce Fields" , Arnd Bergmann , David Howells , Shuah Khan , Shuah Khan , Ingo Molnar , Peter Zijlstra , Christian Brauner , David Drysdale , Andy Lutomirski , Linus Torvalds , Eric Biederman , Andrew Morton , Alexei Starovoitov , Kees Cook , Jann Horn , Tycho Andersen , Chanho Min , Oleg Nesterov , Rasmus Villemoes , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Christian Brauner , Aleksa Sarai , containers@lists.linux-foundation.org, linux-alpha@vger.kernel.org, linux-api@vger.kernel.org, libc-alpha@sourceware.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, sparclinux@vger.kernel.org Subject: Re: [PATCH v15 4/9] namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution Message-ID: <20191113074757.5b4u5vlyx2u6pbn6@yavin.dot.cyphar.com> References: <20191105090553.6350-1-cyphar@cyphar.com> <20191105090553.6350-5-cyphar@cyphar.com> <20191113015534.GA26530@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="odomi6wtik4yoblv" Content-Disposition: inline In-Reply-To: <20191113015534.GA26530@ZenIV.linux.org.uk> Sender: linux-mips-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-mips@vger.kernel.org --odomi6wtik4yoblv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2019-11-13, Al Viro wrote: > Minor nit here - I'd split "move the conditional call of set_root() > into nd_jump_root()" into a separate patch before that one. Makes > for fewer distractions in this one. I'd probably fold "and be > ready for errors other than -ECHILD" into the same preliminary > patch. Will do. > > + /* Not currently safe for scoped-lookups. */ > > + if (unlikely(nd->flags & LOOKUP_IS_SCOPED)) > > + return ERR_PTR(-EXDEV); >=20 > Also a candidate for doing in nd_jump_link()... >=20 > > @@ -1373,8 +1403,11 @@ static int follow_dotdot_rcu(struct nameidata *n= d) > > struct inode *inode =3D nd->inode; > > =20 > > while (1) { > > - if (path_equal(&nd->path, &nd->root)) > > + if (path_equal(&nd->path, &nd->root)) { > > + if (unlikely(nd->flags & LOOKUP_BENEATH)) > > + return -EXDEV; >=20 > Umm... Are you sure it's not -ECHILD? It wouldn't hurt to be -ECHILD -- though it's not clear to me how likely a success would be in REF-walk if the parent components didn't already trigger an unlazy_walk() in RCU-walk. I guess that also means LOOKUP_NO_XDEV should trigger -ECHILD in follow_dotdot_rcu()? --=20 Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH --odomi6wtik4yoblv Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQSxZm6dtfE8gxLLfYqdlLljIbnQEgUCXcu1KgAKCRCdlLljIbnQ EpYSAQDaNIB4LkhLlbFgkuRPiavU6vZ03HuSIHKseqaD6uMARwD+OcGzTDahyjJ6 YeuKal+s33ETzSjupl7K2mKfYQpA2Q0= =nyQ8 -----END PGP SIGNATURE----- --odomi6wtik4yoblv-- 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 C471DC43331 for ; Wed, 13 Nov 2019 07:48:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A501C222C1 for ; Wed, 13 Nov 2019 07:48:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726224AbfKMHsd (ORCPT ); Wed, 13 Nov 2019 02:48:33 -0500 Received: from mout-p-201.mailbox.org ([80.241.56.171]:42250 "EHLO mout-p-201.mailbox.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725966AbfKMHsd (ORCPT ); Wed, 13 Nov 2019 02:48:33 -0500 Received: from smtp2.mailbox.org (smtp2.mailbox.org [IPv6:2001:67c:2050:105:465:1:2:0]) (using TLSv1.2 with cipher ECDHE-RSA-CHACHA20-POLY1305 (256/256 bits)) (No client certificate requested) by mout-p-201.mailbox.org (Postfix) with ESMTPS id 47CcDY3vdYzQlBb; Wed, 13 Nov 2019 08:48:29 +0100 (CET) X-Virus-Scanned: amavisd-new at heinlein-support.de Received: from smtp2.mailbox.org ([80.241.60.241]) by spamfilter05.heinlein-hosting.de (spamfilter05.heinlein-hosting.de [80.241.56.123]) (amavisd-new, port 10030) with ESMTP id 3hMGDl1msr0T; Wed, 13 Nov 2019 08:48:23 +0100 (CET) Date: Wed, 13 Nov 2019 18:47:57 +1100 From: Aleksa Sarai To: Al Viro Cc: Jeff Layton , "J. Bruce Fields" , Arnd Bergmann , David Howells , Shuah Khan , Shuah Khan , Ingo Molnar , Peter Zijlstra , Christian Brauner , David Drysdale , Andy Lutomirski , Linus Torvalds , Eric Biederman , Andrew Morton , Alexei Starovoitov , Kees Cook , Jann Horn , Tycho Andersen , Chanho Min , Oleg Nesterov , Rasmus Villemoes , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Christian Brauner , Aleksa Sarai , containers@lists.linux-foundation.org, linux-alpha@vger.kernel.org, linux-api@vger.kernel.org, libc-alpha@sourceware.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, sparclinux@vger.kernel.org Subject: Re: [PATCH v15 4/9] namei: LOOKUP_BENEATH: O_BENEATH-like scoped resolution Message-ID: <20191113074757.5b4u5vlyx2u6pbn6@yavin.dot.cyphar.com> References: <20191105090553.6350-1-cyphar@cyphar.com> <20191105090553.6350-5-cyphar@cyphar.com> <20191113015534.GA26530@ZenIV.linux.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="odomi6wtik4yoblv" Content-Disposition: inline In-Reply-To: <20191113015534.GA26530@ZenIV.linux.org.uk> Sender: linux-m68k-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-m68k@vger.kernel.org Message-ID: <20191113074757.2gWpbiAYLWmggwKHV3C7ZXPL-DmkN7NJK6lkzaj_m6s@z> --odomi6wtik4yoblv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 2019-11-13, Al Viro wrote: > Minor nit here - I'd split "move the conditional call of set_root() > into nd_jump_root()" into a separate patch before that one. Makes > for fewer distractions in this one. I'd probably fold "and be > ready for errors other than -ECHILD" into the same preliminary > patch. Will do. > > + /* Not currently safe for scoped-lookups. */ > > + if (unlikely(nd->flags & LOOKUP_IS_SCOPED)) > > + return ERR_PTR(-EXDEV); >=20 > Also a candidate for doing in nd_jump_link()... >=20 > > @@ -1373,8 +1403,11 @@ static int follow_dotdot_rcu(struct nameidata *n= d) > > struct inode *inode =3D nd->inode; > > =20 > > while (1) { > > - if (path_equal(&nd->path, &nd->root)) > > + if (path_equal(&nd->path, &nd->root)) { > > + if (unlikely(nd->flags & LOOKUP_BENEATH)) > > + return -EXDEV; >=20 > Umm... Are you sure it's not -ECHILD? It wouldn't hurt to be -ECHILD -- though it's not clear to me how likely a success would be in REF-walk if the parent components didn't already trigger an unlazy_walk() in RCU-walk. I guess that also means LOOKUP_NO_XDEV should trigger -ECHILD in follow_dotdot_rcu()? --=20 Aleksa Sarai Senior Software Engineer (Containers) SUSE Linux GmbH --odomi6wtik4yoblv Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQSxZm6dtfE8gxLLfYqdlLljIbnQEgUCXcu1KgAKCRCdlLljIbnQ EpYSAQDaNIB4LkhLlbFgkuRPiavU6vZ03HuSIHKseqaD6uMARwD+OcGzTDahyjJ6 YeuKal+s33ETzSjupl7K2mKfYQpA2Q0= =nyQ8 -----END PGP SIGNATURE----- --odomi6wtik4yoblv--