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 D8FEECA0EFA for ; Thu, 21 Aug 2025 21:51:51 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 235E7940007; Thu, 21 Aug 2025 17:51:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 20C558E0056; Thu, 21 Aug 2025 17:51:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0FE78940007; Thu, 21 Aug 2025 17:51:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id F0F748E0056 for ; Thu, 21 Aug 2025 17:51:50 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 31AE1C0540 for ; Thu, 21 Aug 2025 21:45:28 +0000 (UTC) X-FDA: 83802096336.13.867FEED Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf26.hostedemail.com (Postfix) with ESMTP id 9688714000C for ; Thu, 21 Aug 2025 21:45:25 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=dRqQIkhv; spf=pass (imf26.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1755812725; 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=xgU+Z5k4KPqEraeKDWCOzJcpc8HGVmW4oZxLQRmx6Ws=; b=zweeVPTkXlFY8ZGjqkALrXM/G7LmRWdtb7XFKQVBOiJzfGHbsbjW+dWpLCuWNxcrZjrvoY o/I7tTBjsIDUZrvbyjaxc+mKzO2KbJefogx821UNkLtxmeLtsJTShIUB+mRIHFe9g/yyZl vxJFY+4sp8p3G/s6MdQy4hIg7hOhEbI= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1755812725; a=rsa-sha256; cv=none; b=fC+gVqW9yND7/A4efcxYL7Yc/bRwlQJcRmB+cgYtk4MW+1GBq2uxrHb3bc0LlyxcJr2UhP RFAp7zp01GJC+PBxbWwNiiYc46vJORosx43am+DHrfpgE4FO73nLo0jfclhsMaaMS9h5i7 P34IsEsHnOW+vnG153nKmzvcTXqLYp4= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=dRqQIkhv; spf=pass (imf26.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1755812724; 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=xgU+Z5k4KPqEraeKDWCOzJcpc8HGVmW4oZxLQRmx6Ws=; b=dRqQIkhvznsxHhME/+IsWavrsBXHmsqA0USw2cVx2/8Cna6y7TDXT7A4V4YY0RH+Vyq445 cqT9YJffSaWiz53FMiq5lWOj7T5uEy3nhzvy3Lhlxxc+eG9yvep4UwD5yR53gAaUEx77Qt 8YtGULrUxS3zsblyXIHRYH0/wkdNEZw= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-670-6sosH_vMPQGCSBnHlgylMw-1; Thu, 21 Aug 2025 17:45:23 -0400 X-MC-Unique: 6sosH_vMPQGCSBnHlgylMw-1 X-Mimecast-MFC-AGG-ID: 6sosH_vMPQGCSBnHlgylMw_1755812722 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-3c380aa1ad1so542125f8f.0 for ; Thu, 21 Aug 2025 14:45:23 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1755812722; x=1756417522; h=content-transfer-encoding:in-reply-to:autocrypt:content-language :references:cc:to:from:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=xgU+Z5k4KPqEraeKDWCOzJcpc8HGVmW4oZxLQRmx6Ws=; b=I77/Nn9VlaR79iYvuRFtW7PLqcZyN2+jmznyMbmgpA6iZLgrLgg0jQF8SPHBu+//3X o/purlw9cqxnaQAgmgO11pTjyUXjebaIAnnUDkDWg3aUHcu8P4KZq7dS9Fjxwd9RvQyd hnwhmeJOSrhm7Aw5G7K11amfEAEfMo9UQJaOvL7FfSKaCPfM0wBorxxzboQqKJJaDJi+ zoKbGsV3XoEkmV4SZpeMQ1zNoVUV+yJx6JfmeCOyFF2IcEFWoBaZ796uBmsEms0rmmLa gjUNu8rHlu2T10bPmUICwmE1rfLbfj5+SzmwMN24sxKbUqleRrAl/TYfjmBALFFyu5/a SBlQ== X-Forwarded-Encrypted: i=1; AJvYcCX73CYyK317N/fUe2rh9aOoqCk47XQMvPeTzwNYQxFTwSpzBEWS2xVrNxW8HwnMnIX628n9fG1QJA==@kvack.org X-Gm-Message-State: AOJu0YzabBuzzfcboP3712KRMp+Psjs4Fc4AaK+KGtHknXRoIHKpBafD sKBrcZHGv8qMIeLw8yZl6LcKxMHW8KtYHQSjARtRoL+hHcZDbWcAV2RWVfh8mrmsjAgqn+wSsxz E2UamtkN3Clt5OetRNoJy5MOFSk9LaCJw5co8X3n6JEERPZbf2q9d X-Gm-Gg: ASbGncsQYCpRoOKP2vddNHz3c39oF2u+/8Lxgb4npj1mihf1AU7EU/suOniILZALDEI f7ou6I4vTu/WJq8W2q6hbcMsH0mBTZcGnkR2v3eUC4+l4a1Lf46zeSixboV8P5arlx+y1OQ0SiA h/MGE13/x2Q62u2RCdTLx12OWsLa+vIKfZoT+Lb1YPeNMNVainvaCyrCfzjoncEDnl2zD7il4Vw nsrCz1yr25hvAqvc6gEeRHbMnQf6REVg1hlbclys5NxU4FcsiCJw1OM7uh7XPiWzWjxZsGHyyaA kb5RaVTbxEkEwwxPh4DySr3SmcltuesNfU2rYtO2M0Z9b0c3Bkif/s8acUEIv84cn96lJUF8xN0 zROPslgqE2rlISpViW441uIwBKD0OmSqPNqolrcfTiKYdOROTsuuAWJBLLA4ELw== X-Received: by 2002:a05:6000:2902:b0:3b8:f925:8d4 with SMTP id ffacd0b85a97d-3c5db2da00amr300070f8f.26.1755812721886; Thu, 21 Aug 2025 14:45:21 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEfnhl0R8ZwVLuxUZYmGD7nMrbthuKRx51tD/iqNpCQL5sxy24UygUdE3xc6j7fC/B+t7+yTQ== X-Received: by 2002:a05:6000:2902:b0:3b8:f925:8d4 with SMTP id ffacd0b85a97d-3c5db2da00amr300045f8f.26.1755812721421; Thu, 21 Aug 2025 14:45:21 -0700 (PDT) Received: from ?IPV6:2003:d8:2f26:ba00:803:6ec5:9918:6fd? (p200300d82f26ba0008036ec5991806fd.dip0.t-ipconnect.de. [2003:d8:2f26:ba00:803:6ec5:9918:6fd]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45b4e25da97sm22067085e9.1.2025.08.21.14.45.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 21 Aug 2025 14:45:20 -0700 (PDT) Message-ID: Date: Thu, 21 Aug 2025 23:45:18 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 33/35] kfence: drop nth_page() usage From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: Alexander Potapenko , Marco Elver , Dmitry Vyukov , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, "Liam R. Howlett" , Linus Torvalds , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Lorenzo Stoakes , Marek Szyprowski , Michal Hocko , Mike Rapoport , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan References: <20250821200701.1329277-1-david@redhat.com> <20250821200701.1329277-34-david@redhat.com> <1a13a5cb-4312-4c01-827b-fa8a029df0f1@redhat.com> 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: <1a13a5cb-4312-4c01-827b-fa8a029df0f1@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 3XaWbA2mhIXUQpoxs_OfMrUorNxs7bnVCzFjEqJHJZs_1755812722 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 9688714000C X-Stat-Signature: qnqd5tec389iuf9itor86bz774rghsat X-HE-Tag: 1755812725-77374 X-HE-Meta: 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 31eHZDmc Wsg478/xXICGp9rBa7cT2ISdTlNFXBGPvsfTWe6vwAiQVyucQXcmK7x5zX/E8XbgaYlh5gKgqsTKaZHzLQmuv1PoEYRwhZyOfLMGew2hMSAX9eFCO/SCyAQMpu3oWtNryAHon8zvaPJ4S8UM4nB3apx+fWsfqxSaSQ3Lr54RQheOK5iXHU04XjeLSRut/XTR6nWe53pd6EaPtrNoNnLjfXNGra0LkuM/pgO5721/gwvIYGsUqSeEuAAB/TodQF2JKmTv60yr83YRI/8/F0ZSOPWA+7Tx5foCUOchN571xFViXRFKiSP9WDUgY2/+c0zi7ir6rBMTMZ0vcLUoIg8tsny8RSKbxbX1KRkvfKM1rRCUS6enN5v9deMjm5zAt+4LzuATrOtDf4qgJZcvPklwjXnFm8CNNQsIL58k6aiP2TZBrRgMTaaYoFsGUKe68/NhfSuw+4rUZplW1KILeLbDjutVrjw0eWLTBgbw9 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 21.08.25 22:32, David Hildenbrand wrote: > On 21.08.25 22:06, David Hildenbrand wrote: >> We want to get rid of nth_page(), and kfence init code is the last user. >> >> Unfortunately, we might actually walk a PFN range where the pages are >> not contiguous, because we might be allocating an area from memblock >> that could span memory sections in problematic kernel configs (SPARSEMEM >> without SPARSEMEM_VMEMMAP). >> >> We could check whether the page range is contiguous >> using page_range_contiguous() and failing kfence init, or making kfence >> incompatible these problemtic kernel configs. >> >> Let's keep it simple and simply use pfn_to_page() by iterating PFNs. >> > > Fortunately this series is RFC due to lack of detailed testing :P > > Something gives me a NULL-pointer pointer here (maybe the virt_to_phys()). > > Will look into that tomorrow. Okay, easy: relying on i but not updating it /me facepalm -- Cheers David / dhildenb