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 B0EAFC433EF for ; Thu, 21 Apr 2022 01:50:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383715AbiDUBw7 (ORCPT ); Wed, 20 Apr 2022 21:52:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357029AbiDUBw6 (ORCPT ); Wed, 20 Apr 2022 21:52:58 -0400 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D7C0055B3 for ; Wed, 20 Apr 2022 18:50:09 -0700 (PDT) Received: from canpemm500002.china.huawei.com (unknown [172.30.72.56]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4KkL396nGfzCrcL; Thu, 21 Apr 2022 09:45:41 +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, 21 Apr 2022 09:50:07 +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> <8e01e276-c956-2486-c55f-c689f33a9106@huawei.com> From: Miaohe Lin Message-ID: <8d180899-9ae2-a38b-3642-ffd057b7acaf@huawei.com> Date: Thu, 21 Apr 2022 09:50:06 +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: dggems706-chm.china.huawei.com (10.3.19.183) 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 2022/4/20 21:32, Peter Xu wrote: > On Wed, Apr 20, 2022 at 02:21:27PM +0800, Miaohe Lin wrote: >> 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. > > I was planning to post a patch after yours since they're touching the same > function, but yeah it'll be great if you could also take that over, thanks! Sure, I will take this in next version. Thanks a lot! :) >