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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD36AC7619A for ; Thu, 13 Apr 2023 01:55:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229791AbjDMBzi (ORCPT ); Wed, 12 Apr 2023 21:55:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47810 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229506AbjDMBzg (ORCPT ); Wed, 12 Apr 2023 21:55:36 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 305DE59ED for ; Wed, 12 Apr 2023 18:55:35 -0700 (PDT) Received: from dggpemm100009.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4PxjLw5zTszDsg7; Thu, 13 Apr 2023 09:54:48 +0800 (CST) Received: from [10.174.179.24] (10.174.179.24) by dggpemm100009.china.huawei.com (7.185.36.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.23; Thu, 13 Apr 2023 09:55:33 +0800 Subject: Re: [PATCH -next] mm: hwpoison: support recovery from HugePage copy-on-write faults To: Andrew Morton , Mike Kravetz References: <20230411092741.780679-1-liushixin2@huawei.com> <20230412181350.GA22818@monkey> <20230412145718.0bcb7dd98112a3010711ad0b@linux-foundation.org> <20230412222138.GB4759@monkey> <20230412155618.720e6b3aa5be6444f7889ea6@linux-foundation.org> CC: Naoya Horiguchi , Tony Luck , Miaohe Lin , Muchun Song , , From: Liu Shixin Message-ID: <5202b6fe-7008-6e1b-eaae-03edbe7c055c@huawei.com> Date: Thu, 13 Apr 2023 09:55:32 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <20230412155618.720e6b3aa5be6444f7889ea6@linux-foundation.org> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.179.24] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemm100009.china.huawei.com (7.185.36.113) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/4/13 6:56, Andrew Morton wrote: > On Wed, 12 Apr 2023 15:21:38 -0700 Mike Kravetz wrote: > >>>> Commit a873dfe1032a ("mm, hwpoison: try to recover from copy-on write >>>> faults") introduced the routine copy_user_highpage_mc() to gracefully >>>> handle copying of user pages with uncorrectable errors. Previously, >>>> such copies would result in a kernel crash. hugetlb has separate code >>>> paths for copy-on-write and does not benefit from the changes made in >>>> commit a873dfe1032a. >> I was just going to suggest adding the line, >> >> Hence, copy-on-write of hugetlb user pages with uncorrectable errors >> will result in a kernel crash as was the case with 'normal' pages before >> commit a873dfe1032a. >> >> However, I'm guessing it might be more clear if we start with the >> runtime effects. Something like: >> >> copy-on-write of hugetlb user pages with uncorrectable errors will result >> in a kernel crash. This is because the copy is performed in kernel mode >> and in general we can not handle accessing memory with such errors while >> in kernel mode. Commit a873dfe1032a ("mm, hwpoison: try to recover from >> copy-on write faults") introduced the routine copy_user_highpage_mc() to >> gracefully handle copying of user pages with uncorrectable errors. However, >> the separate hugetlb copy-on-write code paths were not modified as part >> of commit a873dfe1032a. > Sounds good. So I assume cc:stable is desirable. > > I can't actually get the patch to apply to anything. Can we please > have a redo against current -linus? OK, I will apply this patch to mainline again. > > . >