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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_IN_DEF_DKIM_WL autolearn=ham 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 9426AC433ED for ; Tue, 20 Apr 2021 02:03:15 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 2C21961073 for ; Tue, 20 Apr 2021 02:03:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2C21961073 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id ACB886B0036; Mon, 19 Apr 2021 22:03:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A7CBF6B006E; Mon, 19 Apr 2021 22:03:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 944296B0070; Mon, 19 Apr 2021 22:03:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0162.hostedemail.com [216.40.44.162]) by kanga.kvack.org (Postfix) with ESMTP id 7AF126B0036 for ; Mon, 19 Apr 2021 22:03:14 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 230401DEE for ; Tue, 20 Apr 2021 02:03:14 +0000 (UTC) X-FDA: 78051097908.24.F93C055 Received: from mail-ua1-f47.google.com (mail-ua1-f47.google.com [209.85.222.47]) by imf07.hostedemail.com (Postfix) with ESMTP id 8E7F8A0003A6 for ; Tue, 20 Apr 2021 02:03:13 +0000 (UTC) Received: by mail-ua1-f47.google.com with SMTP id a8so8496266uan.10 for ; Mon, 19 Apr 2021 19:03:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:from:date:message-id:subject:to:cc; bh=SRW6B2l3evCXSdkMXhtncIWNHnatMPLHmgfTJZssxJE=; b=OcZYWiYjOx2mIwK5CtdpMAlAd4IaEvEDFU0TPQO94DzoR647nXkgfjfC/jlmL8SlnU zcwivITDXmDFDv1ihS38tlefhBShQliYmUoAdp791CurT2byJ1krHuikbGQFz/oNWFhM YrxCa/5rz6FsCekyrcW3ZbHLdBOiOyV/bm2/JcwE9N4EuXCPy0XjcYbQB/w7lyeJJCWZ DGIZFHYy2iorq/PohzqJv5eUufvUxytdXBpCjAwS8zVLoGa5o1dJElJXLdmznC1cVo0Q 4EZNTqPheEnb/xbstGSnjdjpOtHCwT62hUNuZ24p+Z35W1tyQ3gJ3CsprI4dIY1iM96f xsfQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to:cc; bh=SRW6B2l3evCXSdkMXhtncIWNHnatMPLHmgfTJZssxJE=; b=qV1Nj45mO3Tvxw3QG+1wuKLFpF8nihxftYnNHTk9FO6m8OiyqDgNDR99FnCLyesSbX JmyFcTQ+QeciBp/vYIr5PgHj6X/+WY3XVZilw88lWAqT1ZJdcU8am4+Jd7L4z57WUbZf PtQHMmoiBPivjTz2eRJbzzy9O5ucjlzPvMoPlR5tYiz3hpqev7ky2iDCVqOhKsc6+twc SOvgjWBB7BS820GuuSksds9/1JGgK5dD4yGYjWIz8D72y8JY8+ZU7oAoaUHBGIdke+ec v34tmx1D1ynsHq0+mKIOK626ba9HJg41y3azWvbvx68wyFvGiEcPc2s+0CP0s682PRL1 g5jQ== X-Gm-Message-State: AOAM531kcD4xDaLG/qzqptUrz0UUN6+yO2Eshz1NVp5JjmS1DR3deRZn /yo1R8AQPpKgvbPpPwt+93QPhmjtypVbCyCtDNvUbA== X-Google-Smtp-Source: ABdhPJwuRmWnDH0KhG10/fSZj/4TzlbSYwhk8Pz+wH6szF4U95OMogzAqlSvjL+IHQAO8+XobgnxG3QIm/nFOhMPGGU= X-Received: by 2002:ab0:7216:: with SMTP id u22mr404027uao.83.1618884192864; Mon, 19 Apr 2021 19:03:12 -0700 (PDT) MIME-Version: 1.0 From: Jue Wang Date: Mon, 19 Apr 2021 19:03:01 -0700 Message-ID: Subject: Re: [PATCH v1 3/3] mm,hwpoison: add kill_accessing_process() to find error virtual address To: nao.horiguchi@gmail.com, "Luck, Tony" Cc: akpm@linux-foundation.org, bp@alien8.de, david@redhat.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, luto@kernel.org, naoya.horiguchi@nec.com, osalvador@suse.de, yaoaili@kingsoft.com Content-Type: text/plain; charset="UTF-8" X-Stat-Signature: 84wpasx5hxagc1e4adpctaz6up85xfgx X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 8E7F8A0003A6 Received-SPF: none (google.com>: No applicable sender policy available) receiver=imf07; identity=mailfrom; envelope-from=""; helo=mail-ua1-f47.google.com; client-ip=209.85.222.47 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1618884193-597285 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 Tue, 13 Apr 2021 07:43:20 +0900, Naoya Horiguchi wrote: > This patch suggests to do page table walk to find the error virtual > address. If we find multiple virtual addresses in walking, we now can't > determine which one is correct, so we fall back to sending SIGBUS in > kill_me_maybe() without error info as we do now. This corner case needs > to be solved in the future. Instead of walking the page tables, I wonder what about the following idea: When failing to get vaddr, memory_failure just ensures the mapping is removed and an hwpoisoned swap pte is put in place; or the original page is flagged with PG_HWPOISONED and kept in the radix tree (e.g., for SHMEM THP). NOTE: no SIGBUS is sent to user space. Then do_machine_check just returns to user space to resume execution, the re-execution will result in a #PF and should land to the exact page fault handling code that generates a SIGBUS with the precise vaddr info: https://github.com/torvalds/linux/blob/7af08140979a6e7e12b78c93b8625c8d25b084e2/mm/memory.c#L3290 https://github.com/torvalds/linux/blob/7af08140979a6e7e12b78c93b8625c8d25b084e2/mm/memory.c#L3647 Thanks, -Jue