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b=ca1RH1W0Wxcxr79uTWniFeOlpGbGmfBugPJpJujCYKxlu04bclqmTJNhVHw7h9pB+ DHKoSm+5eMNlOfS/0BdWb3P+ZgZyY7Es1yP2ZxfcQowENGTcH+IJ+/WvGTev9AG9vv nvKrx7mP71hNGkog1Z7MvYiva/eGZgzKNAw/+od3xHgc+OgsMy/YQKRDCpvZ4tPdEh kbQk2nqBMU4DR7RCFpG+etqh6ctPzXYT+SgqxXXPFhe5PAmzvFoACgwHTJXe35yd+w 7/gykJ+mTXClHcsc1jWX034jHy6qVDn62L0Go4TnuMhshnHWcFGfFEAvzg7wXxZZMb 0w2gujZezj1ZQ== Message-ID: Date: Sun, 31 May 2026 19:23:15 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] mm/gup: honour FOLL_PIN in NOMMU __get_user_pages_locked() To: Andrew Morton Cc: Greg Kroah-Hartman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Jason Gunthorpe , John Hubbard , Peter Xu References: <2026042303-vendor-outright-b9d2@gregkh> <20260424063817.552a894d4b5bfa4de40792fa@linux-foundation.org> <20260526173550.927ba4ba517e9af5a6d2c6bf@linux-foundation.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+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: <20260526173550.927ba4ba517e9af5a6d2c6bf@linux-foundation.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam12 X-Stat-Signature: 61cpqog9ig1eh4oxasamutjdk4qndsbp X-Rspam-User: X-Rspamd-Queue-Id: 79F57A0002 X-HE-Tag: 1780248199-23783 X-HE-Meta: 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 yT7nFoi2 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/27/26 02:35, Andrew Morton wrote: > On Fri, 24 Apr 2026 16:19:32 +0200 "David Hildenbrand (Arm)" wrote: > >> On 4/24/26 15:38, Andrew Morton wrote: >>> >>> >>> Battle of the bots? >>> https://sashiko.dev/#/patchset/2026042303-vendor-outright-b9d2@gregkh >> >> It references the >> >> if (pages && !(flags & FOLL_PIN)) >> flags |= FOLL_GET; >> >> I'm not sure if there is actual NOMMU code that triggers it. For example, >> uprobes uses that pattern, but I suspect that that's not a thing on NOMMU. >> >> >> Probably best to just squash: >> >> diff --git a/mm/gup.c b/mm/gup.c >> index ad9ded39609c..44bd28cf6e00 100644 >> --- a/mm/gup.c >> +++ b/mm/gup.c >> @@ -1988,6 +1988,9 @@ static long __get_user_pages_locked(struct mm_struct *mm, >> unsigned long start, >> if (!nr_pages) >> return 0; >> >> + if (pages && !(foll_flags & FOLL_PIN)) >> + foll_flags |= FOLL_GET; >> + >> /* >> * The internal caller expects GUP to manage the lock internally and the >> * lock must be released when this returns. > > Nothing happened. > > Should we proceed with this as-is? No let's squash what I provided. Probably a resend would be best. If greg is too busy I can give it a try tomorrow. -- Cheers, David