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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D3DEC433EF for ; Wed, 13 Oct 2021 02:49:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 28BDA60F3A for ; Wed, 13 Oct 2021 02:49:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 28BDA60F3A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B339E6B0071; Tue, 12 Oct 2021 22:49:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AE3C56B0072; Tue, 12 Oct 2021 22:49:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9AC026B0073; Tue, 12 Oct 2021 22:49:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0076.hostedemail.com [216.40.44.76]) by kanga.kvack.org (Postfix) with ESMTP id 8F3946B0071 for ; Tue, 12 Oct 2021 22:49:16 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 519D632605 for ; Wed, 13 Oct 2021 02:49:16 +0000 (UTC) X-FDA: 78689882712.28.6D731F4 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf04.hostedemail.com (Postfix) with ESMTP id F13A450000B3 for ; Wed, 13 Oct 2021 02:49:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1634093355; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=R+0oNJdHTqOxAaH5moaEK3403j+y86OhqVlmztOpaVo=; b=g7mVEc47eHmo3A7528ul3lBbanaHhvGRdKx1CGyVH8ugxXMkZy4g47NugWMizRNyHXfMGt vOwEWRX6aRq0ZJKaPGUfs92W944DbXmonE3hESqNEnu4M4Yzz0j971uPJ4Mvj9TNNYBAtL ofEh2eXv6wx5dB2xqU9NXVaFCG7BcM0= Received: from mail-pf1-f198.google.com (mail-pf1-f198.google.com [209.85.210.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-226-kGF9-yjSNaahy7FDvhYBSw-1; Tue, 12 Oct 2021 22:49:12 -0400 X-MC-Unique: kGF9-yjSNaahy7FDvhYBSw-1 Received: by mail-pf1-f198.google.com with SMTP id 4-20020a620504000000b0044be2cfac9bso748187pff.0 for ; Tue, 12 Oct 2021 19:49:12 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=R+0oNJdHTqOxAaH5moaEK3403j+y86OhqVlmztOpaVo=; b=vRM5KOgaBY5f1JSizRK/VHueycKQMZX2Xro3OdqO0J7opyLBZMC6TrE5so+2DsNzf6 fH2nCtyhRJ9FIy6gGx97DOOjbC3AKyOSEX002x8dxcjf7OqE9VOkm7Dt9s/kEftjRbFb OuIc8FClsuRPnttYFT3a1P84qd4DD5nxBglFloHoUUIJR8+YR0/JQ/dvYUoDDYm7+6F0 mjEY62UUBkVVnNs1E5zXcofA0igUbpsAVI6N9cD1IfhY6UwIORgHQ2pV3PQ8aF5r1ggi oMze74LiXXOvFeoVeHdRK7kJBvvoYdBZ2DhaAJgTmskpPz2VidCO5QKG1pNK5XIWIVYW CGKw== X-Gm-Message-State: AOAM531uKJEDw0x2xGSW6gqiKztOaEBsxGynQb1nCSeuVScfD/npHWip u/Q+cNQ5vCKxw6WpIXqqp13X91LNqKBUN14d06dHGqGGcP2tOjTTm0+F7ClIKmeiC6xP3aXP3z2 3MFyXtjDTDiI= X-Received: by 2002:a05:6a00:a0a:b0:44c:52c9:bf25 with SMTP id p10-20020a056a000a0a00b0044c52c9bf25mr35654801pfh.24.1634093351144; Tue, 12 Oct 2021 19:49:11 -0700 (PDT) X-Google-Smtp-Source: ABdhPJyMViZ0sgxMYWlr6yHux2NLvCKNqAhqb/tfqmxDDtN6oX4y3JX1XVULHqOH0ScmrQtPFfn4hA== X-Received: by 2002:a05:6a00:a0a:b0:44c:52c9:bf25 with SMTP id p10-20020a056a000a0a00b0044c52c9bf25mr35654777pfh.24.1634093350788; Tue, 12 Oct 2021 19:49:10 -0700 (PDT) Received: from t490s ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id s8sm4017477pjm.32.2021.10.12.19.49.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Oct 2021 19:49:10 -0700 (PDT) Date: Wed, 13 Oct 2021 10:49:04 +0800 From: Peter Xu To: Naoya Horiguchi Cc: linux-mm@kvack.org, Andrew Morton , Alistair Popple , Mike Kravetz , Konstantin Khlebnikov , Bin Wang , Naoya Horiguchi , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] mm, pagemap: expose hwpoison entry Message-ID: References: <20211004115001.1544259-1-naoya.horiguchi@linux.dev> MIME-Version: 1.0 In-Reply-To: <20211004115001.1544259-1-naoya.horiguchi@linux.dev> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline X-Rspamd-Queue-Id: F13A450000B3 X-Stat-Signature: wqun3o5awdthwq97u9ke9e9o1mfwuntg Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=g7mVEc47; spf=none (imf04.hostedemail.com: domain of peterx@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=peterx@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Rspamd-Server: rspam06 X-HE-Tag: 1634093355-502982 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: Hi, Naoya, On Mon, Oct 04, 2021 at 08:50:01PM +0900, Naoya Horiguchi wrote: > +static inline struct page *hwpoison_entry_to_page(swp_entry_t entry) > +{ > + struct page *p = pfn_to_page(swp_offset(entry)); > + > + WARN_ON(!PageHWPoison(p)); > + return p; > +} This is more a pure question.. I'm wondering whether that WARN_ON() could trigger. IOW, what if we poison an anonymous page and then unpoison it? Will there be a hwpoison swap entry leftover in the ptes that it used to map? Will it crash the program when the page is accessed? I had a feeling that when handling the page fault in do_swap_page before we SIGBUS the program, we should double-check the PageHWPoison on the pfn page, but I could be missing something.. Thanks, -- Peter Xu