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 0CA1FC433EF for ; Thu, 9 Jun 2022 11:28:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243778AbiFIL2i (ORCPT ); Thu, 9 Jun 2022 07:28:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244179AbiFIL23 (ORCPT ); Thu, 9 Jun 2022 07:28:29 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E42FD1EBEF5 for ; Thu, 9 Jun 2022 04:28:27 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4LJhdq2vdkzjXHD; Thu, 9 Jun 2022 19:27:27 +0800 (CST) Received: from [10.174.177.76] (10.174.177.76) by canpemm500002.china.huawei.com (7.192.104.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 9 Jun 2022 19:28:25 +0800 Subject: Re: [PATCH v1 5/5] mm, hwpoison: enable memory error handling on 1GB hugepage To: =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= CC: Naoya Horiguchi , Andrew Morton , David Hildenbrand , Mike Kravetz , Liu Shixin , Yang Shi , Oscar Salvador , Muchun Song , "linux-kernel@vger.kernel.org" , Linux-MM References: <20220602050631.771414-1-naoya.horiguchi@linux.dev> <20220602050631.771414-6-naoya.horiguchi@linux.dev> <20220608061635.GA1413099@hori.linux.bs1.fc.nec.co.jp> <5743855d-8f22-0d82-56c0-1ab61ad431b7@huawei.com> <20220609084556.GA1459006@hori.linux.bs1.fc.nec.co.jp> From: Miaohe Lin Message-ID: Date: Thu, 9 Jun 2022 19:28:25 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.0 MIME-Version: 1.0 In-Reply-To: <20220609084556.GA1459006@hori.linux.bs1.fc.nec.co.jp> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/6/9 16:45, HORIGUCHI NAOYA(堀口 直也) wrote: > On Wed, Jun 08, 2022 at 08:57:24PM +0800, Miaohe Lin wrote: > ... >>> >>> I think that most of page table walker for user address space should first >>> check is_vm_hugetlb_page() and call hugetlb specific walking code for vma >>> with VM_HUGETLB. >>> copy_page_range() is a good example. It calls copy_hugetlb_page_range() >>> for vma with VM_HUGETLB and the function should support hwpoison entry. >>> But I feel that I need testing for confirmation. >> >> Sorry, I missed it should be called from hugetlb variants. >> >>> >>> And I'm not sure that all other are prepared for non-present pud-mapping, >>> so I'll need somehow code inspection and testing for each. >> >> I browsed the code again, there still might be some problematic code paths: >> >> 1.For follow_pud_mask, !pud_present will mostly reach follow_pmd_mask(). This can be >> called for hugetlb page. (Note gup_pud_range is fixed at 15494520b776 ("mm: fix gup_pud_range")) >> >> 2.Even for huge_pte_alloc, pud_offset will be called in pud_alloc. So pudp will be an invalid pointer. >> And it will be de-referenced later. > > Yes, these paths need to support non-present pud entry, so I'll update/add > the patches. It seems that I did the similar work for pmd few years ago > (cbef8478bee5 ("mm/hugetlb: pmd_huge() returns true for non-present hugepage"). Yes, these should be similar work. Thanks for your hard work. :) > > Thanks, > Naoya Horiguchi >