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=-4.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 0E47FC433E0 for ; Wed, 3 Mar 2021 12:24:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EB10D64EBA for ; Wed, 3 Mar 2021 12:24:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EB10D64EBA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kingsoft.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4CEA58D015D; Wed, 3 Mar 2021 07:24:13 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 47F2F8D0157; Wed, 3 Mar 2021 07:24:13 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 31FA98D015D; Wed, 3 Mar 2021 07:24:13 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 188A48D0157 for ; Wed, 3 Mar 2021 07:24:13 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id C62871801F793 for ; Wed, 3 Mar 2021 12:24:12 +0000 (UTC) X-FDA: 77878480344.04.1469ABC Received: from mail.kingsoft.com (mail.kingsoft.com [114.255.44.145]) by imf02.hostedemail.com (Postfix) with ESMTP id 398EE4080F53 for ; Wed, 3 Mar 2021 12:24:02 +0000 (UTC) X-AuditID: 0a580157-f39ff7000005df43-be-603f796e2583 Received: from mail.kingsoft.com (localhost [10.88.1.32]) (using TLS with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mail.kingsoft.com (SMG-1-NODE-87) with SMTP id E5.5F.57155.E697F306; Wed, 3 Mar 2021 19:56:30 +0800 (HKT) Received: from alex-virtual-machine (172.16.253.254) by KSBJMAIL2.kingsoft.cn (10.88.1.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Wed, 3 Mar 2021 20:24:02 +0800 Date: Wed, 3 Mar 2021 20:24:02 +0800 From: Aili Yao To: Andy Lutomirski CC: "Luck, Tony" , Andy Lutomirski , HORIGUCHI NAOYA , Dave Hansen , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , X86 ML , , Linux-MM , LKML , Subject: Re: [PATCH v3] x86/fault: Send a SIGBUS to user process always for hwpoison page access. Message-ID: <20210303202402.384265a3@alex-virtual-machine> In-Reply-To: <59469ECC-5316-4074-98EF-52FFF7940818@amacapital.net> References: <8d0c76f97f35499f91a2b82d3e7c024d@intel.com> <59469ECC-5316-4074-98EF-52FFF7940818@amacapital.net> Organization: kingsoft X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Originating-IP: [172.16.253.254] X-ClientProxiedBy: KSBJMAIL1.kingsoft.cn (10.88.1.31) To KSBJMAIL2.kingsoft.cn (10.88.1.32) X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrAIsWRmVeSWpSXmKPExsXCFcGooJtXaZ9g0PBYzOLzhn9sFi82tDNa TNsobnF51xw2i3tr/rNarF7bwGpxftdaVotLBxYwWVxsPMBocbz3AJPF5k1TmS3eXLjHYvFj w2NWB16P7619LB733/xl8di8Qstj8Z6XTB6bVnWyeWz6NInd4925c+we804Gery4upHF4/2+ q2wenzfJeZxo+cIawBPFZZOSmpNZllqkb5fAldHTvIW54AJXxY1T/9kbGNdxdDFyckgImEjc 3TiVvYuRi0NIYDqTRP/WHmYI5yWjxM5vfSxdjBwcLAIqEtO+GYE0sAmoSuy6N4sVxBYR0JR4 OWU+C0g9s8BLZoltb2YxgySEBZIlzkx6wAhi8wpYSXS0bQGLcwo4SRyfs5EJxBYSKJD42dLI AmLzC4hJ9F75zwRxkb1E25ZFUL2CEidnPgGrYQZa1rr9NzuErS2xbOFrZog5ihKHl/xih+hV kjjSPYMNwo6VWDbvFesERuFZSEbNQjJqFpJRCxiZVzGyFOemG25ihERi+A7GeU0f9Q4xMnEw HmKU4GBWEuEVf2mbIMSbklhZlVqUH19UmpNafIhRmoNFSZy3xck+QUggPbEkNTs1tSC1CCbL xMEp1cDEOucYx61ojSWTj4aHpl34o8HWONfo3R3TpMPSU7/7rzD4djQ/fxfnG7c9Rc82Vi5Y rXH/nqnchyAe33mbn0hvrzn9bP4K7f8XahYssNdQt/jX7Kr4d13x4SfMC3hyJ0yYuLLU6bXn 68mvDkbU8/BJBu264h1mHet4dOnH/2Z6xatSW++/m8tbt6n80q003xkMieZbbZfu4N2z+nz1 dc7qXz+23f839/jcyb+dznyT7TjaP03Llsvv5N6dG6f4OjltP+NabZaZLVKxh+3uGj2+DdOd zA/NSPdL2pcnvV6CVX2rsthWIxWOzhLmkJNf6/ekz6jL++08/4FL2wfFs3nvEud0zP+pfcU/ 5PYKs42u1kosxRmJhlrMRcWJAEUw0kwzAwAA X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 398EE4080F53 X-Stat-Signature: hh7dzykgd94jcohgx5b7z94ja9pqiqci Received-SPF: none (kingsoft.com>: No applicable sender policy available) receiver=imf02; identity=mailfrom; envelope-from=""; helo=mail.kingsoft.com; client-ip=114.255.44.145 X-HE-DKIM-Result: none/none X-HE-Tag: 1614774242-59705 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, 1 Mar 2021 11:09:36 -0800 Andy Lutomirski wrote: > > On Mar 1, 2021, at 11:02 AM, Luck, Tony wrote: > >=20 > > =EF=BB=BF =20 > >>=20 > >> Some programs may use read(2), write(2), etc as ways to check if > >> memory is valid without getting a signal. They might not want > >> signals, which means that this feature might need to be configurable. = =20 > >=20 > > That sounds like an appalling hack. If users need such a mechanism > > we should create some better way to do that. > > =20 >=20 > Appalling hack or not, it works. So, if we=E2=80=99re going to send a sig= nal to user code that looks like it originated from a bina fide architectur= al recoverable fault, it needs to be recoverable. A load from a failed NVD= IMM page is such a fault. A *kernel* load is not. So we need to distinguish= it somehow. Sorry for my previous mis-understanding, and i have some questions:=20 if programs use read,write to check if if memory is valid, does it really w= ant to cover the poison case?=20 When for such a case, an error is returned, can the program realize it's h= wposion issue not other software error and process correctly? if this is the proper action, the original posion flow in current code from= read and write need to change too. --=20 Thanks! Aili Yao