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[87.161.172.195]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3b76fcad2b4sm3213491f8f.47.2025.07.24.14.32.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 24 Jul 2025 14:32:30 -0700 (PDT) Message-ID: Date: Thu, 24 Jul 2025 23:32:29 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/5] mm/mseal: update madvise() logic To: Kees Cook , Lorenzo Stoakes Cc: Andrew Morton , "Liam R . Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jeff Xu References: <202507241352.22634450C9@keescook> 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmgsLPQFCRvGjuMACgkQTd4Q 9wD/g1o0bxAAqYC7gTyGj5rZwvy1VesF6YoQncH0yI79lvXUYOX+Nngko4v4dTlOQvrd/vhb 02e9FtpA1CxgwdgIPFKIuXvdSyXAp0xXuIuRPQYbgNriQFkaBlHe9mSf8O09J3SCVa/5ezKM OLW/OONSV/Fr2VI1wxAYj3/Rb+U6rpzqIQ3Uh/5Rjmla6pTl7Z9/o1zKlVOX1SxVGSrlXhqt kwdbjdj/csSzoAbUF/duDuhyEl11/xStm/lBMzVuf3ZhV5SSgLAflLBo4l6mR5RolpPv5wad GpYS/hm7HsmEA0PBAPNb5DvZQ7vNaX23FlgylSXyv72UVsObHsu6pT4sfoxvJ5nJxvzGi69U s1uryvlAfS6E+D5ULrV35taTwSpcBAh0/RqRbV0mTc57vvAoXofBDcs3Z30IReFS34QSpjvl Hxbe7itHGuuhEVM1qmq2U72ezOQ7MzADbwCtn+yGeISQqeFn9QMAZVAkXsc9Wp0SW/WQKb76 FkSRalBZcc2vXM0VqhFVzTb6iNqYXqVKyuPKwhBunhTt6XnIfhpRgqveCPNIasSX05VQR6/a OBHZX3seTikp7A1z9iZIsdtJxB88dGkpeMj6qJ5RLzUsPUVPodEcz1B5aTEbYK6428H8MeLq NFPwmknOlDzQNC6RND8Ez7YEhzqvw7263MojcmmPcLelYbfOwU0EVcufkQEQAOfX3n0g0fZz 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+DWgUCaCwtJQUJG8aPFAAKCRBN3hD3AP+DWlDnD/4k2TW+HyOOOePVm23F5HOhNNd7nNv3 Vq2cLcW1DteHUdxMO0X+zqrKDHI5hgnE/E2QH9jyV8mB8l/ndElobciaJcbl1cM43vVzPIWn 01vW62oxUNtEvzLLxGLPTrnMxWdZgxr7ACCWKUnMGE2E8eca0cT2pnIJoQRz242xqe/nYxBB /BAK+dsxHIfcQzl88G83oaO7vb7s/cWMYRKOg+WIgp0MJ8DO2IU5JmUtyJB+V3YzzM4cMic3 bNn8nHjTWw/9+QQ5vg3TXHZ5XMu9mtfw2La3bHJ6AybL0DvEkdGxk6YHqJVEukciLMWDWqQQ RtbBhqcprgUxipNvdn9KwNpGciM+hNtM9kf9gt0fjv79l/FiSw6KbCPX9b636GzgNy0Ev2UV m00EtcpRXXMlEpbP4V947ufWVK2Mz7RFUfU4+ETDd1scMQDHzrXItryHLZWhopPI4Z+ps0rB CQHfSpl+wG4XbJJu1D8/Ww3FsO42TMFrNr2/cmqwuUZ0a0uxrpkNYrsGjkEu7a+9MheyTzcm vyU2knz5/stkTN2LKz5REqOe24oRnypjpAfaoxRYXs+F8wml519InWlwCra49IUSxD1hXPxO WBe5lqcozu9LpNDH/brVSzHCSb7vjNGvvSVESDuoiHK8gNlf0v+epy5WYd7CGAgODPvDShGN g3eXuA== Organization: Red Hat In-Reply-To: <202507241352.22634450C9@keescook> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: fMbLiM28aKZ0Fq71gm5dS_8FmAbxhS35rQfuOyN131w_1753392751 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-Rspamd-Queue-Id: D34474000C X-Stat-Signature: eotjwzphzz4fa17oksua8h19o7seqrjh X-Rspam-User: X-HE-Tag: 1753392754-392381 X-HE-Meta: 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 G9kf+Pao 3oYFXtGzFeqRO9fxbynBj0r6/aKdJuFtPslTTYsJAVgMiptDrSbdvbS+uy29OAh9/AAT9Yh9If96N43VE9i10s9AQ5TUv08cYEQCZg69/CZpMgFBjyywBQgAK9ge+ZZsFLf+SNwrvQDax/OSoDmHK0HXkCnURWZb/zPGRHrBigv06hqkSyRy4P3O+BTUNp2uQL5AWqHLXjrY5c7wVNZ6hvgbI9JzcwytUPOf3gCpl5vcZEl89/igc1FMNuCkRNmpS+2BNbiQUt2N1ZvEY9ZSNC9BTqIvDy56sAVsju+4VjRQr7nzrYVC29X2+B6oaWQ8ggJ2p7tLiTt2AtU89h/SXiQRBPM/QzGQ3CEZoBCE4p73x8zVP5UVUFemLOOZN+vtRRLfusQNdUAgEI4Mb4S4BDxY4Np8udAhohqaQoIDtWbsVwFo= 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: > As an aside, why should discard work in this case even without step 4? > Wouldn't setting "read-only" imply you don't want the memory to change > out from under you? I guess I'm not clear on the semantics: how do memory > protection bits map to madvise actions like this? They generally don't affect MADV_DONTNEED behavior. The only documented (man page) reason for EPERM in the man page is related to MADV_HWPOISON. -- Cheers, David / dhildenb