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 A1AF0CCA47B for ; Thu, 14 Jul 2022 10:00:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231574AbiGNJ77 (ORCPT ); Thu, 14 Jul 2022 05:59:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231356AbiGNJ74 (ORCPT ); Thu, 14 Jul 2022 05:59:56 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A571DE29 for ; Thu, 14 Jul 2022 02:59:55 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Lk8zd3qkgzhZ0n; Thu, 14 Jul 2022 17:57:17 +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, 14 Jul 2022 17:59:53 +0800 Subject: Re: [PATCH] mm/hugetlb: avoid corrupting page->mapping in hugetlb_mcopy_atomic_pte To: Andrew Morton CC: , , , , Axel Rasmussen , Peter Xu References: <20220712130542.18836-1-linmiaohe@huawei.com> <20220713102357.8328614813db01b569650ffd@linux-foundation.org> From: Miaohe Lin Message-ID: Date: Thu, 14 Jul 2022 17:59:53 +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: <20220713102357.8328614813db01b569650ffd@linux-foundation.org> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit 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 2022/7/14 1:23, Andrew Morton wrote: > On Tue, 12 Jul 2022 21:05:42 +0800 Miaohe Lin wrote: > >> In MCOPY_ATOMIC_CONTINUE case with a non-shared VMA, pages in the page >> cache are installed in the ptes. But hugepage_add_new_anon_rmap is called >> for them mistakenly because they're not vm_shared. This will corrupt the >> page->mapping used by page cache code. > > Well that sounds bad. And theories on why this has gone unnoticed for > over a year? I assume this doesn't have coverage in our selftests? As discussed in another thread, when minor fault handling is proposed, only VM_SHARED vma is expected to be supported. And the test case is also missing. Thanks. > >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -6038,7 +6038,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, >> if (!huge_pte_none_mostly(huge_ptep_get(dst_pte))) >> goto out_release_unlock; >> >> - if (vm_shared) { >> + if (page_in_pagecache) { >> page_dup_file_rmap(page, true); >> } else { >> ClearHPageRestoreReserve(page); >> -- >> 2.23.0 > . >