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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EDA87CA0FF0 for ; Mon, 1 Sep 2025 07:22:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1F2E08E0006; Mon, 1 Sep 2025 03:22:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1A35B8E0003; Mon, 1 Sep 2025 03:22:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 06B0B8E0006; Mon, 1 Sep 2025 03:22:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id E27F58E0003 for ; Mon, 1 Sep 2025 03:22:52 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 8634F1406EC for ; Mon, 1 Sep 2025 07:22:52 +0000 (UTC) X-FDA: 83839839384.14.48B40A1 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf23.hostedemail.com (Postfix) with ESMTP id 35245140002 for ; Mon, 1 Sep 2025 07:22:50 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=QesRIq+3; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1756711370; a=rsa-sha256; cv=none; b=M+zVdjlo20fdwSLjyXSCRaUFGjjp0C070LCqm8lFr+zq2LYQROBEi6fL4KwZNv0PHPtXYF ntfJeMuEu/Pb8/3kYiWkxpVoMZ1KIElRXl+04u1IUia6gajeVKbtZhNvIG4uCToOzurRWC UOrydFbgsbpFDceX05iB6t1EjIcz6LE= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=QesRIq+3; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf23.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756711370; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=9V4R05sdobHBJHmAx3r85pkYP3EzkYBt4hLu36K3MfI=; b=4LQ9aTgMQEr+CgXxBJqYr8y7ILJ/o8v/UkdDCFZ2ZtCKTo+iPzKHMui4hsKf+cY+JzXmfs lnYahmG41lvoWbgsUHpKbfjmgBIXmjgsx40bK1G0QQnSU9DDFc50IXs9VF9JieXBtDzPAl zrI0VOHr0HqS4nJ92WyETPorn+rEhz4= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756711369; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=9V4R05sdobHBJHmAx3r85pkYP3EzkYBt4hLu36K3MfI=; b=QesRIq+3o10cszTZBvWbkKwgZOwrko4b/imL+7PR1CfaxEX1H03qdV7OKBDtexjYyUyKIi HmvYm5RWyKoy+HdurAQDPdp60UMsvBUsjYL8xnSa5OB0GT8i4a4jJBq0cqFnuMHYJYuVF4 jyJVc13SVjHOE5V0SgM4ivBKvzKhdus= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-649-VS5vtgB7OaCJGmOSqF8Tcw-1; Mon, 01 Sep 2025 03:22:48 -0400 X-MC-Unique: VS5vtgB7OaCJGmOSqF8Tcw-1 X-Mimecast-MFC-AGG-ID: VS5vtgB7OaCJGmOSqF8Tcw_1756711367 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3ccfd90630aso1690260f8f.3 for ; Mon, 01 Sep 2025 00:22:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756711367; x=1757316167; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :from:references:cc:to:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=9V4R05sdobHBJHmAx3r85pkYP3EzkYBt4hLu36K3MfI=; b=SAqe2DOqwdefRGJJzFpfMu4xWNeuXgn0aoB9CQB79CS3KnwKLbpRbEsVBW/TRaQx9G t3YnA9Oj4cDC15IapmY0JZpCAnTqO/tFI6yawJcYL/JylhK/ORcZQrFDMenTjfpE4mYb zlmU+MULfpiBxGJRGPfrW8hsffLFHBcB5wWhWGavwb32HxBGNgE6BJlt8OLhOdbsOZvP aRg0wXLxK4Q0RpSaD8LgScHdsu00Mqvc01/7G7avq2ywaiqUIOIB3wz/2e4fwPfTIi0k GxO3F6Iwc2f1D2i1FGldNNHLrpUSHGRR/uYnxud1rOYUxCnByFEkOSZp9NtNON59yDrY hJ+g== X-Gm-Message-State: AOJu0YyDrrEDJxmHVepM0MGxBi/isnTvmpRG3pqQjwLo8bC9gC+NQSFv bkpXNEbkcJObv9KyXoPOQxb2YLG/K4UyBIye9kRgm1obqeC/RBRNG3Ptpglv2vZAkL5YUXNLDCH Znlgub8mrnOSiQRO79y6P+xofJ8t3AmDFIdNYaoURamNlxngJR80h X-Gm-Gg: ASbGncvXSGdMV9Lm/qzC8DZge24xg9cGAPDTI1P4nevF0oQz7FFr3ozzu7muyyxeAXW 6Ne8v7B6zLhRq5IIub/rIZo6XSkQu5u72FGa9BfLT4M5X4tlMJnl0AQebK9bH2sNKy+/NySaFtb LFtnf4X2M5waOIojFmkwFq9axQ5iJg3ks4QT2sSpSC4p5xq+6SPq85c+qlw8pkZ+jsS04uqsFdQ i+1RVsf3nzgEfmDLccs5bIFxJLI6tU9BOwg91SFUm5NANwtzTVgfQXLLUXh0ZefZakn2svs0x3o 6moEser3Tld59puvzUSga1G70EajerTivKn5iNQMRGSaNjSrZgp7xL9Or5p5ItIuT4wuXAC7I/W bDpET15bYYVunLP/sdNj4OKchMEMELUBtnRNsiLwInrEmXBk9816wjvbLOcvPxC2jG0k= X-Received: by 2002:a05:6000:42c9:b0:3d1:e22d:df2f with SMTP id ffacd0b85a97d-3d1e22e12d1mr3737085f8f.23.1756711367089; Mon, 01 Sep 2025 00:22:47 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFVNYjwWcm6gpW0uY4rkHHxrCMQOJdbdQbgUiX4+ObJzl258/8a6I3ZT74/QxiH1Rpl4yYyjg== X-Received: by 2002:a05:6000:42c9:b0:3d1:e22d:df2f with SMTP id ffacd0b85a97d-3d1e22e12d1mr3737072f8f.23.1756711366670; Mon, 01 Sep 2025 00:22:46 -0700 (PDT) Received: from ?IPV6:2003:d8:2f37:2b00:948c:dd9f:29c8:73f4? (p200300d82f372b00948cdd9f29c873f4.dip0.t-ipconnect.de. [2003:d8:2f37:2b00:948c:dd9f:29c8:73f4]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3cf33fb9cebsm13932480f8f.46.2025.09.01.00.22.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 01 Sep 2025 00:22:45 -0700 (PDT) Message-ID: Date: Mon, 1 Sep 2025 09:22:44 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [Patch v2] selftests/mm: check content to see whether mremap corrupt data To: Wei Yang , akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <20250831022701.2595-1-richard.weiyang@gmail.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20250831022701.2595-1-richard.weiyang@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: cOdmCqeIRTY1IA3EN4rPK252RbvV5n4kgCZQFPIJdLc_1756711367 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 35245140002 X-Stat-Signature: k7ndgjn9ank8yz8by8ojcm44n43kbizq X-HE-Tag: 1756711370-375742 X-HE-Meta: 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 At3U2Nx+ 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 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: List-Subscribe: List-Unsubscribe: On 31.08.25 04:27, Wei Yang wrote: Subject: "selftests/mm: verify page content after remapping PMD through PTEs" > After mremap(), add a check on content to see whether mremap corrupt > data. > > Signed-off-by: Wei Yang > > --- > v2: add check on content instead of just test backed folio I'm confused, don't we have that exact check later in the function? Your v1 might have been better, unless I am missing something. > --- > tools/testing/selftests/mm/split_huge_page_test.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c > index 10ae65ea032f..229b6dcabece 100644 > --- a/tools/testing/selftests/mm/split_huge_page_test.c > +++ b/tools/testing/selftests/mm/split_huge_page_test.c > @@ -423,10 +423,14 @@ static void split_pte_mapped_thp(void) > > /* smap does not show THPs after mremap, use kpageflags instead */ > thp_size = 0; > - for (i = 0; i < pagesize * 4; i++) > + for (i = 0; i < pagesize * 4; i++) { > + if (pte_mapped[i] != (char)i) > + ksft_exit_fail_msg("%ld byte corrupted\n", i); > + > if (i % pagesize == 0 && > is_backed_by_folio(&pte_mapped[i], pmd_order, pagemap_fd, kpageflags_fd)) > thp_size++; > + } > > if (thp_size != 4) > ksft_exit_fail_msg("Some THPs are missing during mremap\n"); I'm a bit confused with this test in general. We do a pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE); which I read as a "NOP". Questions (a) Will this actually do anything? Also, maybe it does now, but can't the kernel just optimize that out in the future? (b) Is it even guaranteed that we can access > pagesize afterwards? I mean, we specify MREMAP_MAYMOVE. I would suggest to just use mprotect/madvise to pte-map a PMD-THP. This is, of course, independent of this patch. -- Cheers David / dhildenb