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 B1926195FE5 for ; Mon, 20 Jan 2025 14:01:19 +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=1737381681; cv=none; b=L4CCUTqyJMW6c6PmGAG/j2j0yk+5IUt2+q5jcYScZnMZw8dznuHC4M/sv8A6OlbkcBGnDPI/wePFEzS8/EubmRmw7QMDgY0XZY0O4c9ZwEC2i4OY6b/gN/iSmpXlnFQR1KMiVwVXUqwrUJxqWWM2+z6i9rZnEi7HVS03HnZXzqU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737381681; c=relaxed/simple; bh=P/dX7qtKmEZ3b9p7HzcprzzFKMRKPpP8C8n4ecr+VbE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qOTjg5IaZ8XhXP2NfYpg7umwE8fYtOBWgdzg9gtqGiikLCHc5mJ24oLKyQepPS1wOdLnfZKIMTppfKKDryq+M32CbFnxqbTeAHXFEC1LBzllXPVJzOsevJRngfYsKV57f6od9UY+rIWOWn0dvFfahBgn0KSJlUZPBhWRqtNVdZs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=bnJRcm2M; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="bnJRcm2M" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1737381678; 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=s/mkn72W8t1XUEbeDrh1A3farpkJnU2/T6YwPc/jj1M=; b=bnJRcm2MBTXRkcZEERROuTjWY1qRsha55aO6l/faEIG65dueedlkighJq2IG0+eMCESpC0 P7V9nHs9iRCA9YUmJv5waXgJNky6O2HLEnHWbBbxG7ddY5HlQFtk2CwOVZNbOQeRExIaVZ ph+zBqdFq2yWkBPpOVq5CmThidACTyQ= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-456-0NUSycWJPDiNBTK-xaU7pg-1; Mon, 20 Jan 2025 09:01:17 -0500 X-MC-Unique: 0NUSycWJPDiNBTK-xaU7pg-1 X-Mimecast-MFC-AGG-ID: 0NUSycWJPDiNBTK-xaU7pg Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-385d52591d6so1886828f8f.1 for ; Mon, 20 Jan 2025 06:01:16 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737381676; x=1737986476; h=content-transfer-encoding:in-reply-to:organization: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=s/mkn72W8t1XUEbeDrh1A3farpkJnU2/T6YwPc/jj1M=; b=RI4ANVFnsDTEn14eHuMVXvdwq1AEvn1sLDAkGUXDknHDTWw+fH6qMGvIFOcLoUcSt2 wT5JIvbr5Mv7GaVpfYr8Aq1pQVV0AL0rz4p3qAEGmhFw8s77pjq2P6LfSGCjMByV4TRT 0j06LykzGAwnLPupINhCQarqe5Q/kNQB0cfHnVG7ZA+HXZw+baViAUBz32XgNsAloFRX +NKdGOZiRozOEdTv1vpmdOeAunXMbmkzskJebuPaA0pHBlKDfZa0T5C/RB0TTURuzqZ4 NCTWdPXgvKv+N8FIZVmGlkCUCdtYxD7QrTvsbUSAQG/cqnOKjKyOo1NBIG4Ab17w/3fr PYYg== X-Forwarded-Encrypted: i=1; AJvYcCWPYgx6vvkZ5xghJDn7VkBbLNL4Pfm27fTABE+6oJhANl6nPOHRIEaj4tI37xA8M207VP8NpoUEQZ8qBBs=@vger.kernel.org X-Gm-Message-State: AOJu0YwGK9/3C10cnoS/S1NiJfusLzo3kDRPuRizvdlpnnzkzc86S5bq bF+6Uxv8tD6ZcdUMdM2H+GeRDGkj4+5o/XCLt4+fvEI48RgTH4+mrpMOpa0KJquwr539tfHvqN5 XwPpk6iaRfnQZU1FBJmAaGGPXfnnggeDaedqqSXig0ycYCOWEI086ta+akSoH2A== X-Gm-Gg: ASbGncvLPIUCA2HXFBArc4wpCUINNJ33Vpl6czRZTEdGeECcabl1vNKxf0nVUMINEGa 9GceB0Bs8i74pznhdoJDRl3QaQKLCZJ/OgOLIE/WjEjRkk3FdFsIspDqj5isK/b0hRZTpCuRSZk B6BFYYfBDhSiukP9CmHwMoevs4TB6qWvYYDEauhLU41SodW87NlXqdJ/iSxGVZx/Lt9zq96mjhj nu/42vkp6ERDZs1QU+7eX6gVfmCd4rzRgaKHqQLoQydCI9G76Qw/BhctFO7Az+fIdTbd/Ra2J5r s+oCsgcy3UrGBpcZHMS1waKYodWU4qUA4oTguwhO+A7hJkmVw3t4uqqCEFqtfh+ASW3ocvP6xC9 fqnrQTj4vQqJyUq9vwV54KA== X-Received: by 2002:a5d:64ad:0:b0:38a:5dc4:6dcd with SMTP id ffacd0b85a97d-38bf5b02b35mr11556562f8f.22.1737381674258; Mon, 20 Jan 2025 06:01:14 -0800 (PST) X-Google-Smtp-Source: AGHT+IEkvpw6N9bbmfHHasViK+AHy/K6leeD0foDQE8jUVDigAwqhSf9+Yp1CRL595t8b3c+PzTPbg== X-Received: by 2002:a5d:64ad:0:b0:38a:5dc4:6dcd with SMTP id ffacd0b85a97d-38bf5b02b35mr11556158f8f.22.1737381670471; Mon, 20 Jan 2025 06:01:10 -0800 (PST) Received: from ?IPV6:2003:d8:2f22:1000:d72d:fd5f:4118:c70b? (p200300d82f221000d72dfd5f4118c70b.dip0.t-ipconnect.de. [2003:d8:2f22:1000:d72d:fd5f:4118:c70b]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38bf3221b70sm10384941f8f.26.2025.01.20.06.01.07 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Jan 2025 06:01:09 -0800 (PST) Message-ID: <3964f3ff-ce24-4656-ae4b-bc9ffdf6532a@redhat.com> Date: Mon, 20 Jan 2025 15:01:07 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 1/2] mm: Clear uffd-wp PTE/PMD state on mremap() To: Ryan Roberts , Peter Xu Cc: Andrew Morton , Muchun Song , "Liam R. Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Shuah Khan , =?UTF-8?Q?Miko=C5=82aj_Lenczewski?= , Mark Rutland , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, stable@vger.kernel.org References: <20250107144755.1871363-1-ryan.roberts@arm.com> <20250107144755.1871363-2-ryan.roberts@arm.com> <873aede9-bfcd-4c95-a93d-ec1881554f39@arm.com> From: David Hildenbrand 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <873aede9-bfcd-4c95-a93d-ec1881554f39@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 16.01.25 10:04, Ryan Roberts wrote: > On 15/01/2025 20:28, Peter Xu wrote: >> On Tue, Jan 07, 2025 at 02:47:52PM +0000, Ryan Roberts wrote: >>> When mremap()ing a memory region previously registered with userfaultfd >>> as write-protected but without UFFD_FEATURE_EVENT_REMAP, an >>> inconsistency in flag clearing leads to a mismatch between the vma flags >>> (which have uffd-wp cleared) and the pte/pmd flags (which do not have >>> uffd-wp cleared). This mismatch causes a subsequent mprotect(PROT_WRITE) >>> to trigger a warning in page_table_check_pte_flags() due to setting the >>> pte to writable while uffd-wp is still set. >>> >>> Fix this by always explicitly clearing the uffd-wp pte/pmd flags on any >>> such mremap() so that the values are consistent with the existing >>> clearing of VM_UFFD_WP. Be careful to clear the logical flag regardless >>> of its physical form; a PTE bit, a swap PTE bit, or a PTE marker. Cover >>> PTE, huge PMD and hugetlb paths. >>> >>> Co-developed-by: Mikołaj Lenczewski >>> Signed-off-by: Mikołaj Lenczewski >>> Signed-off-by: Ryan Roberts >>> Closes: https://lore.kernel.org/linux-mm/810b44a8-d2ae-4107-b665-5a42eae2d948@arm.com/ >>> Fixes: 63b2d4174c4a ("userfaultfd: wp: add the writeprotect API to userfaultfd ioctl") >>> Cc: stable@vger.kernel.org >> >> Nothing I see wrong: >> >> Reviewed-by: Peter Xu > > Great thanks! Thanks Peter, for your feedback while I was out. I remember that I skimmed over it without anything obvious jumping at me, but decided to set it aside for later to take a closer look .... which never happened. Took another look, and it looks good to me! (we really must clear the uffd-wp flags when losing the VMA flag) -- Cheers, David / dhildenb