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[2003:d8:2f1f:3f00:731a:f5e5:774e:d40c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3cf33fb9db4sm18611700f8f.47.2025.09.02.00.49.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 02 Sep 2025 00:49:49 -0700 (PDT) Message-ID: Date: Tue, 2 Sep 2025 09:49:48 +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 Cc: Zi Yan , akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, baolin.wang@linux.alibaba.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <20250831022701.2595-1-richard.weiyang@gmail.com> <61E58B7C-23D0-49FE-8D0C-CE0B672114E2@nvidia.com> <0a0b0018-9427-4201-bf53-6aeb251bc482@redhat.com> <1D88E773-C11E-4F28-A13A-1A681898198B@nvidia.com> <5a796574-0a3c-4040-b0bc-3ff757402759@redhat.com> <20250902025112.d2n3o4imeptppctd@master> 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: <20250902025112.d2n3o4imeptppctd@master> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: CIn0mcqb7zrigqRsJbbzJoEfFFfI0Uaqnlo-NkVzPcs_1756799390 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: o8nmxqtm7zswf3djtc5jubtbk6kdr9cd X-Rspam-User: X-Rspamd-Queue-Id: 6355240002 X-Rspamd-Server: rspam05 X-HE-Tag: 1756799393-82428 X-HE-Meta: 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 0JSQOWBa HQeTK2SKApIGUuJhUhmkiT+oEiQbhFikWE8qXbpjXWxtlCLp1M9kwuiA/e3sqzR+1nRrgq0W0o1BJi+3+WeqQ1y6fk2HnaNn65Nqday4VhCnOQFomQ/7aJrApSy3CbYcWFQ3tUAnFuH/h88Yv/f1NejCk4VSBR/f4uKJzu5qNZoyiZ+z4FkULWMd1FRQGX5hqjXZku8JbnvPqvFIakJFnjFGhaUZGciD9w+PbyvWRFU2mpCFfY9lkb5UBLafVdkcZDs39lF1JqpwHooDImSaCNou0B9u/ZG7+FG5YaQgnuXlSMm76QeAaJuNcfepEtxnCPL+WzW8yXPNi/sueG1YRq3ESZrtDpN/ecGrR5vZJFmdAu6+1Uugxzqt40sL3WpoKZfupRdmC+a6R1XtCpBCVq+CcC3UGzDjJoF1tRxhBtEDwCx3e4lt88ERXBrMGA8i4qssWh1BK/cgJ+26AAz08O4B2BuGJsnFXe4XEw5ARsoNidVfNSymCJz2oQw== 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: >> + /* >> + * To challenge spitting code, we will mremap page[x] of the >> + * thp[x] into a smaller area, and trigger the split from that >> + * smaller area. This will end up replacing the PMD mappings in >> + * the thp_area by PTE mappings first, leaving the THPs unsplit. >> + */ >> + page_area = mmap(NULL, page_area_size, PROT_READ | PROT_WRITE, >> + MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); >> + if (page_area == MAP_FAILED) { >> + ksft_test_result_fail("Fail to allocate memory: %s\n", strerror(errno)); >> + goto out; >> + } >> - if (i % pagesize == 0 && >> - !is_backed_by_folio(&pte_mapped[i], 0, pagemap_fd, kpageflags_fd)) >> - thp_size++; >> + for (i = 0; i < nr_thps; i++) { >> + tmp = mremap(thp_area + pmd_pagesize * i + pagesize * i, >> + pagesize, pagesize, MREMAP_MAYMOVE|MREMAP_FIXED, >> + page_area + pagesize * i); > > Would this create one hole at the beginning of each 2M range and cause > splitting underlining THP? Yes, it will create a hole (this also happens in the old code). As the comment above it now states: "leaving the THPs unsplit" There is a check verifying that after this mremap code. -- Cheers David / dhildenb