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,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 0DF5FC433DB for ; Thu, 11 Mar 2021 01:19:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A38A964FA6 for ; Thu, 11 Mar 2021 01:19:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A38A964FA6 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 F15268D025E; Wed, 10 Mar 2021 20:19:47 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EC5C08D0250; Wed, 10 Mar 2021 20:19:47 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D66338D025E; Wed, 10 Mar 2021 20:19:47 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0065.hostedemail.com [216.40.44.65]) by kanga.kvack.org (Postfix) with ESMTP id BC2898D0250 for ; Wed, 10 Mar 2021 20:19:47 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 77364181AEF2A for ; Thu, 11 Mar 2021 01:19:47 +0000 (UTC) X-FDA: 77905836414.22.F5F3BE0 Received: from mail.kingsoft.com (unknown [114.255.44.146]) by imf21.hostedemail.com (Postfix) with ESMTP id 52F2DE0001B4 for ; Thu, 11 Mar 2021 01:19:43 +0000 (UTC) X-AuditID: 0a580155-1f5ff7000005482e-6d-604968aae979 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-2-NODE-85) with SMTP id 4C.75.18478.AA869406; Thu, 11 Mar 2021 08:47:38 +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 15.1.2176.2; Thu, 11 Mar 2021 09:19:41 +0800 Date: Thu, 11 Mar 2021 09:19:41 +0800 From: Aili Yao To: Andy Lutomirski CC: "Luck, Tony" , Oleg Nesterov , Linux API , 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: <20210311091941.45790fcf@alex-virtual-machine> In-Reply-To: <047D5B49-FDBB-494C-81E9-DA811476747D@amacapital.net> References: <4fc1b4e8f1fb4c8c81f280db09178797@intel.com> <047D5B49-FDBB-494C-81E9-DA811476747D@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+NgFlrBIsWRmVeSWpSXmKPExsXCFcGooLsqwzPBYMZZIYvPG/6xWbzY0M5o MW2juMXm7x1sFpd3zWGzuLfmP6vF6rUNrBbnd61ltbh0YAGTxcXGA4wWW/e3Mloc7z3AZLF5 01RmizcX7rFY/NjwmNWB3+N7ax+Lx/03f1k8Nq/Q8li85yWTx6ZVnWwemz5NYvd4d+4cu8e8 k4EeL65uZPF4v+8qm8fnTXIeJ1q+sAbwRHHZpKTmZJalFunbJXBlnLptXvCWp+LWpNPsDYwt XF2MnBwSAiYSb96uZ+xi5OIQEpjOJLG9dSkTSEJI4BWjxLxjoSA2i4CqxImV8xlBbDYge9e9 WawgtoiApsTLKfNZQJqZBU6zSLTt6QYrEhZIljgz6QGYzStgJfFs11k2EJtTwEni/M9PQA0c QAsKJKafCAEJ8wuISfRe+c8EcZC9RNuWRVCtghInZz5hAbGZgXa1bv/NDmFrSyxb+JoZ4k5F icNLfrFD9CpJHOmewQZhx0osm/eKdQKj8Cwko2YhGTULyagFjMyrGFmKc9ONNjFCIjN0B+OM po96hxiZOBgPMUpwMCuJ8Podd0sQ4k1JrKxKLcqPLyrNSS0+xCjNwaIkzrv3mGuCkEB6Yklq dmpqQWoRTJaJg1OqgUnQSUF4Voulk8S9KR7SZsJCB/Pd1lufniYo3ZeZE/pGZ9+8rdlMc/pq PDoDJ898IVhkrh3iymBRyuAXmmde1PtzmTLPl7j0O9tP8ShbWU7/93Tmottf/u7OSbSaaKFV NE/aV6P8dtEGo+KjV529jc5NeihZsqnp7P7qjnU+56tcz6ckeE56qDevpj5zdfmSDX5ztV5O bhDwYwzVM7Psk72SHGcUeK2PK8JTbL12mMFBof8fruWLmZ6NkAu+feHhYoboRdcPPfOJyPbK yFTSeM/yqsUzUr0j+A1zfPbn1ybp0/4JCTBHzt1enJl/h6nc/Duf/BOXc2e0J7eeD558h709 Xnk2z7fzD1N85xUpsRRnJBpqMRcVJwIA7iPl1zsDAAA= X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 52F2DE0001B4 X-Stat-Signature: 1cwfrg3xjw487nngqyk9rgtiyq8fb1js Received-SPF: none (kingsoft.com>: No applicable sender policy available) receiver=imf21; identity=mailfrom; envelope-from=""; helo=mail.kingsoft.com; client-ip=114.255.44.146 X-HE-DKIM-Result: none/none X-HE-Tag: 1615425583-269523 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, 8 Mar 2021 11:00:28 -0800 Andy Lutomirski wrote: > > On Mar 8, 2021, at 10:31 AM, Luck, Tony wrote: > >=20 > > =EF=BB=BF =20 > >>=20 > >> Can you point me at that SIGBUS code in a current kernel? =20 > >=20 > > It is in kill_me_maybe(). mce_vaddr is setup when we disassemble whate= ver get_user() > > or copy from user variant was in use in the kernel when the poison memo= ry was consumed. > >=20 > > if (p->mce_vaddr !=3D (void __user *)-1l) { > > force_sig_mceerr(BUS_MCEERR_AR, p->mce_vaddr, PAGE_SHIFT= ); =20 >=20 > Hmm. On the one hand, no one has complained yet. On the other hand, hardw= are that supports this isn=E2=80=99t exactly common. >=20 > We may need some actual ABI design here. We also need to make sure that t= hings like io_uring accesses or, more generally, anything using the use_mm = / use_temporary_mm ends up either sending no signal or sending a signal to = the right target. >=20 > >=20 > > Would it be any better if we used the BUS_MCEERR_AO code that goes into= siginfo? =20 >=20 > Dunno. I have one thought here but don't know if it's proper: Previous patch use force_sig_mceerr to the user process for such a scenario= ; with this method The SIGBUS can't be ignored as force_sig_mceerr() was designed to. If the user process don't want this signal, will it set signal config to ig= nore? Maybe we can use a send_sig_mceerr() instead of force_sig_mceerr(), if proc= ess want to ignore the SIGBUS, then it will ignore that, or it can also process the SIG= BUS? --=20 Thanks! Aili Yao