From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BA7582EA463 for ; Thu, 21 Aug 2025 21:45:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755812728; cv=none; b=Zx98Ew6PXBGTfBJhYjEWPO84P22aL01hrNEBP8K4czJEOnqSfCK1dBKk0fI4WS3gZWkWoY9Xu9JGk5sLU+RJReDPo7O5hjbs+4SacAssJmbHyVjLeTRioMX8VVdUUWcfckEoTZ77vV5wcQvYE2TwrV0H2Y+8QwNX4U779Qrr/9I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755812728; c=relaxed/simple; bh=fUaBHZHAJdUQk9eKwml7s0QHGPPoV73wuBZAYASLp2c=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=mitMLYQB2KEJA4MmMRpjDH/1HIX2QOwFi6MLXt2fVNIGQnHsQ9NQcZ7Q7mhqwC3k4Auwy00Sj8pK7i7S2UGAskwiAllrg3BW8Rm9kRnhLjnmkgFGRn43eCXhSN8Sz++JhBjJ1bGds1viiE8uwelb201Feo8y6isjLLoDcNM0Md4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=dRqQIkhv; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dRqQIkhv" 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-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-670-A7BfVHPcNAOrVK6G1VluiQ-1; Thu, 21 Aug 2025 17:45:23 -0400 X-MC-Unique: A7BfVHPcNAOrVK6G1VluiQ-1 X-Mimecast-MFC-AGG-ID: A7BfVHPcNAOrVK6G1VluiQ_1755812722 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-3b9dc56225aso857470f8f.1 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=mU8S5Phd1D47TPjgTcXagEgvbU/mvFmqjJVUIfjN0Yjv4J4+Vf2q8yIcS9+IV2ke52 9fhEh7uPks4w6zvJTDUfLivaWUlUXGbLRc6AO2O8GmA2A+UQg1WZc7lNY5fcVzo4Z0uQ UlpltslFnRTKc46YF3ijMqE+qgHNW2c++/3Cn7NOH9hn9rq0osJUUgXBDic7Z8hKDg0k zO8KSCAGpth6/yN+HZ1opINesuvl70TKbZaTnf8TethfzI+yhh6AK2lx1rZNRt+BXimH tjv+lQb49hG+QNWMBsJxVIM2ygFeN1kFbsAJApGbNYJCWg0Q6D9j+eoSs7sNLxdUC0wE Tmew== X-Forwarded-Encrypted: i=1; AJvYcCU02D8ZVK3DZIO+MxBP0D5UgLg7276cm/NxzFGwa6/UENFr26NvzZoRS97/K1gTC/uK8OmTcwvJDww=@vger.kernel.org X-Gm-Message-State: AOJu0YwSdixfr0My6/BnBr6Bd3X+fLxwddj0kCvVVIOQizS4eMfwIJz2 cN1td/lnXH83raF+afp+4ReMyIOzf/mLjozFoSpB9ex3Pnevy2x9LCXdprSrdY6amRj/brtDktU g59FKvnq1KgehWxoQI7Osbe5uTdCOAMvl0KAM05f4fDSzCyrcUc/2oskNsOn7hw== X-Gm-Gg: ASbGncsOizc4+AbumOu8iLlnbn2QtADr+obfuQM0dthElYSXw/doYq2bIhkwM41C8k8 oKx+gwEPF/FYLvarAIWWKM3eZD8GivYbqwG2M1yaFSOaucljB5lXiO3yjsTixBKzMgGU1AuRZdJ CJaMROVuzOlAWzE/xJiGfVciVg8fWAtWUvW/ktue3Jh4E4LUmMw/HDkPudPbBKwuLLi9QWvCWNI jUpQj0auDsDSaG33pTOSB9JHKHJ6fIn2f6ZKAWoCm2u46x7PonhSNgpBPZVmsmaAL2oQwhOapiA OKoG3iN9mxsZpmAjfuqZuq+1EixPSUm9MZIaPa5hGMWzeacekX6QLnMVmAzxrDSZalft6/r+xpZ vN1Na4UKLV8tyikBu8wnrc2x7m7oJ2ugk5+kEtPl9tc0IKgHo/D0V9dkSFxBiog== X-Received: by 2002:a05:6000:2902:b0:3b8:f925:8d4 with SMTP id ffacd0b85a97d-3c5db2da00amr300066f8f.26.1755812721881; 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 Precedence: bulk X-Mailing-List: linux-mmc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> Content-Language: en-US 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> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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