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=-9.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=unavailable 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 54CB7C433DB for ; Wed, 10 Mar 2021 08:02:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 268A064FF1 for ; Wed, 10 Mar 2021 08:02:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229725AbhCJIBk convert rfc822-to-8bit (ORCPT ); Wed, 10 Mar 2021 03:01:40 -0500 Received: from mail.kingsoft.com ([114.255.44.146]:47226 "EHLO mail.kingsoft.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S229828AbhCJIBL (ORCPT ); Wed, 10 Mar 2021 03:01:11 -0500 X-AuditID: 0a580155-20dff7000005482e-38-604875472f08 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 9E.D3.18478.74578406; Wed, 10 Mar 2021 15:29:11 +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; Wed, 10 Mar 2021 16:01:08 +0800 Date: Wed, 10 Mar 2021 16:01:07 +0800 From: Aili Yao To: "HORIGUCHI =?UTF-8?B?TkFPWUE=?=(=?UTF-8?B?5aCA5Y+j44CA55u05Lmf?=)" CC: "Luck, Tony" , Oscar Salvador , "david@redhat.com" , "akpm@linux-foundation.org" , "bp@alien8.de" , "tglx@linutronix.de" , "mingo@redhat.com" , "hpa@zytor.com" , "x86@kernel.org" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "yangfeng1@kingsoft.com" , , Subject: Re: [PATCH v2] mm,hwpoison: return -EBUSY when page already poisoned Message-ID: <20210310160107.7383a6f4@alex-virtual-machine> In-Reply-To: <20210309082824.GA1793@hori.linux.bs1.fc.nec.co.jp> References: <20210305093016.40c87375@alex-virtual-machine> <20210305093656.6c262b19@alex-virtual-machine> <20210305221143.GA220893@agluck-desk2.amr.corp.intel.com> <20210308064558.GA3617@hori.linux.bs1.fc.nec.co.jp> <3690ece2101d428fb9067fcd2a423ff8@intel.com> <20210308223839.GA21886@hori.linux.bs1.fc.nec.co.jp> <20210308225504.GA233893@agluck-desk2.amr.corp.intel.com> <20210309100421.3d09b6b1@alex-virtual-machine> <20210309060440.GA29668@hori.linux.bs1.fc.nec.co.jp> <20210309143534.6c1a8ec5@alex-virtual-machine> <20210309082824.GA1793@hori.linux.bs1.fc.nec.co.jp> 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: 8BIT 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+NgFprLIsWRmVeSWpSXmKPExsXCFcGooOte6pFgMP0dm8Wc9WvYLD5v+Mdm 8XX9L2aLaRvFLS6camCyuLxrDpvFvTX/WS0uHVjAZHGx8QCjxZlpRRabN01ltnhz4R6LxY8N j1kdeD2+t/axeCze85LJY9OqTjaPTZ8msXu8O3eO3ePEjN8sHi+ubmTxeL/vKpvH5tPVHp83 yXmcaPnCGsAdxWWTkpqTWZZapG+XwJWxc887xoLFohVXnx9ga2DcJ9DFyMkhIWAiseDrHaYu Ri4OIYHpTBJr5x9hgXBeMUq0PV3CDlLFIqAq8fbWDzYQmw3I3nVvFiuILSKQJLF49lewbmaB 7ywSrcdvgRUJC/hL/HnwF6yIV8BK4vGcSWA2p4CDxI2rjawQG86xSEza0c8CkuAXEJPovfKf CeIme4m2LYsYIZoFJU7OfAJWwyygKdG6/Tc7hK0tsWzha2YQW0hAUeLwkl/sEL1KEke6Z7BB 2LESy+a9Yp3AKDwLyahZSEbNQjJqASPzKkaW4tx0o02MkBgM3cE4o+mj3iFGJg7GQ4wSHMxK Irx+x90ShHhTEiurUovy44tKc1KLDzFKc7AoifPuPeaaICSQnliSmp2aWpBaBJNl4uCUamA6 V1qseLlQpFaeafafTs5mCcUk9TPB+TLbPlVe8Au9ZvnGasPOu0KrY3kYa/7JqZobzm21VfF4 u07g9lR9z2P80ldOJUkarVF8Fv8iVMkqah/fo1b2q7saVnh+EpVpnbDpWUwW/0X/fdK3V3ex vb7TvSlE7FrhFOlD+szVZslFPW2sGw8vLzM7s2NCxKvKSN5mMaOneZrrZDxlvoZd9Io4r2DS rLmEf3n1mv+Klw3FpyT255iX8XVw77JqWfH50Erua+l6ru9nexzVsvus7yEga8t2/kH3T/fH XJtS5Jao9Kr7PJ0euZrfsvvAdUXXw+3/tjCuv2lx6IX0PZWN/JnnXr727Xu77uHFpRYiB5VY ijMSDbWYi4oTAfVKR04wAwAA Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 9 Mar 2021 08:28:24 +0000 HORIGUCHI NAOYA(堀口　直也) wrote: > On Tue, Mar 09, 2021 at 02:35:34PM +0800, Aili Yao wrote: > > When the page is already poisoned, another memory_failure() call in the > > same page now return 0, meaning OK. For nested memory mce handling, this > > behavior may lead to mce looping, Example: > > > > 1.When LCME is enabled, and there are two processes A && B running on > > different core X && Y separately, which will access one same page, then > > the page corrupted when process A access it, a MCE will be rasied to > > core X and the error process is just underway. > > > > 2.Then B access the page and trigger another MCE to core Y, it will also > > do error process, it will see TestSetPageHWPoison be true, and 0 is > > returned. > > > > 3.The kill_me_maybe will check the return: > > > > 1244 static void kill_me_maybe(struct callback_head *cb) > > 1245 { > > > > 1254 if (!memory_failure(p->mce_addr >> PAGE_SHIFT, flags) && > > 1255 !(p->mce_kflags & MCE_IN_KERNEL_COPYIN)) { > > 1256 set_mce_nospec(p->mce_addr >> PAGE_SHIFT, > > p->mce_whole_page); > > 1257 sync_core(); > > 1258 return; > > 1259 } > > > > 1267 } > > > > 4. The error process for B will end, and may nothing happened if > > kill-early is not set, The process B will re-excute instruction and get > > into mce again and then loop happens. And also the set_mce_nospec() > > here is not proper, may refer to commit fd0e786d9d09 ("x86/mm, > > mm/hwpoison: Don't unconditionally unmap kernel 1:1 pages"). > > > > For other cases which care the return value of memory_failure() should > > check why they want to process a memory error which have already been > > processed. This behavior seems reasonable. > > Other reviewers shared ideas about the returned value, but actually > I'm not sure which the best one is (EBUSY is not that bad). > What we need to fix the reported issue is to return non-zero value > for "already poisoned" case (the value itself is not so important). > > Other callers of memory_failure() (mostly test programs) could see > the change of return value, but they can already see EBUSY now and > anyway they should check dmesg for more detail about why failed, > so the impact of the change is not so big. > > > > > Signed-off-by: Aili Yao > > Reviewed-by: Naoya Horiguchi > > Thanks, > Naoya Horiguchi Thanks! And I found my mail was lost in mailist! -- Thanks! Aili Yao