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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id ECE91C433EF for ; Wed, 20 Apr 2022 06:21:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4E4956B0074; Wed, 20 Apr 2022 02:21:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 46CFE6B0075; Wed, 20 Apr 2022 02:21:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 341956B0078; Wed, 20 Apr 2022 02:21:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id 22FDD6B0074 for ; Wed, 20 Apr 2022 02:21:32 -0400 (EDT) Received: from smtpin01.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id E27A62239B for ; Wed, 20 Apr 2022 06:21:31 +0000 (UTC) X-FDA: 79376260782.01.CB98C32 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) by imf17.hostedemail.com (Postfix) with ESMTP id 3ABC14000D for ; Wed, 20 Apr 2022 06:21:29 +0000 (UTC) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.55]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4KjrBz4shRz1J9q9; Wed, 20 Apr 2022 14:20:43 +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; Wed, 20 Apr 2022 14:21:27 +0800 Subject: Re: [PATCH v2] mm/swapfile: unuse_pte can map random data if swap read fails To: Peter Xu CC: , , , , , , , , , , , , , References: <20220416030549.60559-1-linmiaohe@huawei.com> From: Miaohe Lin Message-ID: <8e01e276-c956-2486-c55f-c689f33a9106@huawei.com> Date: Wed, 20 Apr 2022 14:21:27 +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: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.174.177.76] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To canpemm500002.china.huawei.com (7.192.104.244) X-CFilter-Loop: Reflected Authentication-Results: imf17.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf17.hostedemail.com: domain of linmiaohe@huawei.com designates 45.249.212.255 as permitted sender) smtp.mailfrom=linmiaohe@huawei.com X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 3ABC14000D X-Stat-Signature: 5mg4k89d4i549zxzt6m86c4cjxjtg5o3 X-HE-Tag: 1650435689-627290 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 2022/4/20 5:36, Peter Xu wrote: > On Sat, Apr 16, 2022 at 11:05:49AM +0800, Miaohe Lin wrote: >> @@ -1797,6 +1797,17 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, >> goto out; >> } >> >> + if (unlikely(!PageUptodate(page))) { >> + pte_t pteval; >> + >> + dec_mm_counter(vma->vm_mm, MM_SWAPENTS); >> + pteval = swp_entry_to_pte(make_swapin_error_entry(page)); >> + set_pte_at(vma->vm_mm, addr, pte, pteval); >> + swap_free(entry); >> + ret = 0; >> + goto out; >> + } >> + >> /* See do_swap_page() */ >> BUG_ON(!PageAnon(page) && PageMappedToDisk(page)); >> BUG_ON(PageAnon(page) && PageAnonExclusive(page)); > > Totally off-topic, but.. today when I was looking at the unuse path I just > found that the swp bits could have got lost for either soft-dirty and > uffd-wp here? A quick patch attached. Am I supposed to test-and-send this patch? The patch looks good to me except the build error pointed out by kernel test robot. > > Maybe at some point we should start to have some special helpers for > set_pte_at() when we're converting between present/non-present ptes, so as > to make sure all these will always be taken care of properly. That will be helpful. There are many places doing the similar thing. > Thanks!