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=-15.1 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 2087AC433C1 for ; Fri, 26 Mar 2021 14:09:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id AD04E619BF for ; Fri, 26 Mar 2021 14:09:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AD04E619BF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1991C6B0070; Fri, 26 Mar 2021 10:09:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 14D026B0071; Fri, 26 Mar 2021 10:09:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F07416B0072; Fri, 26 Mar 2021 10:09:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0082.hostedemail.com [216.40.44.82]) by kanga.kvack.org (Postfix) with ESMTP id D1D506B0070 for ; Fri, 26 Mar 2021 10:09:31 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 8A11718027A77 for ; Fri, 26 Mar 2021 14:09:31 +0000 (UTC) X-FDA: 77962208142.21.E077052 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf22.hostedemail.com (Postfix) with ESMTP id C0180C0007E3 for ; Fri, 26 Mar 2021 14:09:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1616767767; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Z7QwucvE9nb3RtYI6S5g6QloEEtiiTCmIsioM4emDvQ=; b=JF1GkGXzWjNzN4EdUW/CJ0yVEd50oe85J5Fb6jN30LB22kO2wco3SGQ61c5CY+k8Evpc2D Lne9BfAr49r0GdIBUMbWulnX/EBuapaAYeXT4WqwXEjPvGmDuJc77pnEdarVYvC5eyk9lh hoE7z/suz/UeeZ64nO9p81dAyfOee90= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-6-BcaHSwW6Nc6esEc7igM1ag-1; Fri, 26 Mar 2021 10:09:25 -0400 X-MC-Unique: BcaHSwW6Nc6esEc7igM1ag-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C793E190D341; Fri, 26 Mar 2021 14:09:23 +0000 (UTC) Received: from [10.36.112.81] (ovpn-112-81.ams2.redhat.com [10.36.112.81]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9235A5D9DE; Fri, 26 Mar 2021 14:09:19 +0000 (UTC) To: Aili Yao , Matthew Wilcox , akpm@linux-foundation.org, naoya.horiguchi@nec.com Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, yangfeng1@kingsoft.com, sunhao2@kingsoft.com, Oscar Salvador , Mike Kravetz References: <20210317163714.328a038d@alex-virtual-machine> <20a0d078-f49d-54d6-9f04-f6b41dd51e5f@redhat.com> <20210318044600.GJ3420@casper.infradead.org> <20210318133412.12078eb7@alex-virtual-machine> <20210319104437.6f30e80d@alex-virtual-machine> <20210320003516.GC3420@casper.infradead.org> <20210322193318.377c9ce9@alex-virtual-machine> From: David Hildenbrand Organization: Red Hat GmbH Subject: Re: [PATCH v5] mm/gup: check page hwposion status for coredump. Message-ID: Date: Fri, 26 Mar 2021 15:09:18 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210322193318.377c9ce9@alex-virtual-machine> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: C0180C0007E3 X-Stat-Signature: wfcti4ut4497ft7g1i1czuuao8b5cfaw Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf22; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=170.10.133.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1616767766-430383 Content-Transfer-Encoding: quoted-printable 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 22.03.21 12:33, Aili Yao wrote: > When we do coredump for user process signal, this may be one SIGBUS sig= nal > with BUS_MCEERR_AR or BUS_MCEERR_AO code, which means this signal is > resulted from ECC memory fail like SRAR or SRAO, we expect the memory > recovery work is finished correctly, then the get_dump_page() will not > return the error page as its process pte is set invalid by > memory_failure(). >=20 > But memory_failure() may fail, and the process's related pte may not be > correctly set invalid, for current code, we will return the poison page= , > get it dumped, and then lead to system panic as its in kernel code. >=20 > So check the hwpoison status in get_dump_page(), and if TRUE, return NU= LL. >=20 > There maybe other scenario that is also better to check hwposion status > and not to panic, so make a wrapper for this check, Thanks to David's > suggestion(). >=20 > Link: https://lkml.kernel.org/r/20210319104437.6f30e80d@alex-virtual-ma= chine > Signed-off-by: Aili Yao > Cc: David Hildenbrand > Cc: Matthew Wilcox > Cc: Naoya Horiguchi > Cc: Oscar Salvador > Cc: Mike Kravetz > Cc: Aili Yao > Cc: stable@vger.kernel.org > Signed-off-by: Andrew Morton > --- > mm/gup.c | 4 ++++ > mm/internal.h | 20 ++++++++++++++++++++ > 2 files changed, 24 insertions(+) >=20 > diff --git a/mm/gup.c b/mm/gup.c > index e4c224c..6f7e1aa 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -1536,6 +1536,10 @@ struct page *get_dump_page(unsigned long addr) > FOLL_FORCE | FOLL_DUMP | FOLL_GET); > if (locked) > mmap_read_unlock(mm); Thinking again, wouldn't we get -EFAULT from __get_user_pages_locked()=20 when stumbling over a hwpoisoned page? See __get_user_pages_locked()->__get_user_pages()->faultin_page(): handle_mm_fault()->vm_fault_to_errno(), which translates=20 VM_FAULT_HWPOISON to -EFAULT, unless FOLL_HWPOISON is set (-> -EHWPOISON) ? > + > + if (ret =3D=3D 1 && is_page_hwpoison(page)) > + return NULL; > + > return (ret =3D=3D 1) ? page : NULL; > } > #endif /* CONFIG_ELF_CORE */ > diff --git a/mm/internal.h b/mm/internal.h > index 25d2b2439..b751cef 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -97,6 +97,26 @@ static inline void set_page_refcounted(struct page *= page) > set_page_count(page, 1); > } > =20 > +/* > + * When kernel touch the user page, the user page may be have been mar= ked > + * poison but still mapped in user space, if without this page, the ke= rnel > + * can guarantee the data integrity and operation success, the kernel = is > + * better to check the posion status and avoid touching it, be good no= t to > + * panic, coredump for process fatal signal is a sample case matching = this > + * scenario. Or if kernel can't guarantee the data integrity, it's bet= ter > + * not to call this function, let kernel touch the poison page and get= to > + * panic. > + */ > +static inline bool is_page_hwpoison(struct page *page) > +{ > + if (PageHWPoison(page)) > + return true; > + else if (PageHuge(page) && PageHWPoison(compound_head(page))) > + return true; > + > + return false; > +} > + > extern unsigned long highest_memmap_pfn; > =20 > /* >=20 --=20 Thanks, David / dhildenb