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a="188739273" X-IronPort-AV: E=Sophos;i="5.81,241,1610438400"; d="scan'208";a="188739273" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Mar 2021 09:05:55 -0800 IronPort-SDR: UnBMPMNAmjlV2lOgE13+gfTJozcsEO11D+J/l9JEvw33mJDqzC0k9EivlWoaoCOoaNpc9n0Wfa PAmHtPuL316g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.81,241,1610438400"; d="scan'208";a="372391140" Received: from fmsmsx606.amr.corp.intel.com ([10.18.126.86]) by orsmga006.jf.intel.com with ESMTP; 11 Mar 2021 09:05:55 -0800 Received: from fmsmsx610.amr.corp.intel.com (10.18.126.90) by fmsmsx606.amr.corp.intel.com (10.18.126.86) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Thu, 11 Mar 2021 09:05:54 -0800 Received: from fmsmsx610.amr.corp.intel.com (10.18.126.90) by fmsmsx610.amr.corp.intel.com (10.18.126.90) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Thu, 11 Mar 2021 09:05:54 -0800 Received: from fmsmsx610.amr.corp.intel.com ([10.18.126.90]) by fmsmsx610.amr.corp.intel.com ([10.18.126.90]) with mapi id 15.01.2106.013; Thu, 11 Mar 2021 09:05:54 -0800 From: "Luck, Tony" To: =?iso-2022-jp?B?SE9SSUdVQ0hJIE5BT1lBKBskQktZOH0hIUQ+TGkbKEIp?= , Aili Yao CC: 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] mm,hwpoison: return -EBUSY when page already poisoned Thread-Topic: [PATCH] mm,hwpoison: return -EBUSY when page already poisoned Thread-Index: AQHXCnz5ja9ELypBUEatGW66U99st6pnoa2AgAEgN4CAAIHfAIAAAyEAgAAQXwD//9g7gIABDSmAgAALNoCAB2DqAIAAiu0AgABOzQD//+3L0IABObiAgAAiT4CAACi3AIAAmjmAgACgEACAAGnOwIAHwDQAgAHAYACAAADA4A== Date: Thu, 11 Mar 2021 17:05:53 +0000 Message-ID: References: <20210303115710.2e9f8e23@alex-virtual-machine> <20210303163912.3d508e0f@alex-virtual-machine> <1a78e9abdc134e35a5efcbf6b2fd2263@intel.com> <20210304101653.546a9da1@alex-virtual-machine> <20210304121941.667047c3@alex-virtual-machine> <20210304144524.795872d7@alex-virtual-machine> <20210304235720.GA215567@agluck-desk2.amr.corp.intel.com> <20210305093016.40c87375@alex-virtual-machine> <20210310141042.4db9ea29@alex-virtual-machine> <20210311085529.GA22268@hori.linux.bs1.fc.nec.co.jp> In-Reply-To: <20210311085529.GA22268@hori.linux.bs1.fc.nec.co.jp> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: dlp-product: dlpe-windows dlp-reaction: no-action dlp-version: 11.5.1.3 x-originating-ip: [10.1.200.100] Content-Type: text/plain; charset="iso-2022-jp" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Stat-Signature: 1g7q7udsk9pahyqaz5p7qf5dyuefb7r5 X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: A961BE005F05 Received-SPF: none (intel.com>: No applicable sender policy available) receiver=imf13; identity=mailfrom; envelope-from=""; helo=mga03.intel.com; client-ip=134.134.136.65 X-HE-DKIM-Result: none/none X-HE-Tag: 1615482365-938390 X-Bogosity: Ham, tests=bogofilter, spamicity=0.001028, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: > I guess that p->mce_vaddr stores the virtual address of the error here. > If so, sending SIGBUS with the address looks enough as we do now, so why > do you walk page table to find the error virtual address? p->mce_vaddr only has the virtual address for the COPYIN case. In that code path we decode the kernel instruction that hit the fault in order to find t= he virtual address. That's easy because: 1) The kernel RIP is known to be good (can't page fault etc. on kernel addr= ess). 2) There are only a half dozen instructions used by the kernel for get_user= () or copy_from_user(). When the machine check happens during user execution accessing poison data we only have the physical address (from MCi_ADDR). -Tony