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b=Sb130OWgpLFTr086vbrLVXDhGiRA2dFSsHxqYeZBWauuRNcSjrFQrGGAtw5EDC35W Ak5kGmct0g6a7aLxgxxFzmcA5klESXyRsveDz02QnGkV/ivzRCLyULq5U7eh7qjmSp 0A0tGP+WpQ5RopLOLvHQrZoMHPGQ+2Ca1vMNfLQxeKhw89KSR4Xy7e+lo2fC9XEh4+ 4G9zU13ZEDYzRHTJaolR730wl1UjowNWpni0qSvubT3UrCLo0zD5Iq7P0UKP+TAv8Q nMHrIOOL/cCP3jYgh4equZva18wEsxoivNzug1cqropFjNpfOPDYX2lUH3KVhJX9W9 +//n0WlqHinqg== Message-ID: Date: Wed, 4 Feb 2026 20:18:14 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: WARNING in memory_failure() at include/linux/huge_mm.h:635 triggered To: Zi Yan Cc: =?UTF-8?B?5piv5Y+C5beu?= , linux-mm@kvack.org, linmiaohe@huawei.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, Matthew Wilcox References: <1db245a8-f9ab-42e4-8cc6-cc7562961921@kernel.org> <48978612-6933-4897-85DD-6740B6C8570B@nvidia.com> <25CA4D90-A24E-49C6-92D2-08080EC81466@nvidia.com> <032058DC-CD8D-406A-B986-740E41C834B2@nvidia.com> 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: <032058DC-CD8D-406A-B986-740E41C834B2@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 26096C0004 X-Rspamd-Server: rspam07 X-Stat-Signature: cxad9s35umx6kwyn6dqtf59ok3f35r3q X-HE-Tag: 1770232699-77729 X-HE-Meta: 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 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: On 2/4/26 18:41, Zi Yan wrote: > On 4 Feb 2026, at 12:34, Zi Yan wrote: > >> On 4 Feb 2026, at 12:23, Zi Yan wrote: >> >>> >>> >>> From the C repro above, syzbot opened a dev "/dev/sg#" and did mmap on it. >>> Is it a device driver issue? >> >> OK, it is CONFIG_CHR_DEV_SG. And the driver allocates a compound page at[1]. >> Since we initialize folio fields in prep_compound_page(), it becomes a folio >> when it is inserted into a VMA. > > More details: > later at sg_vma_fault(), the driver just handles a page fault by supplying > a subpage from a pre-allocated compound page[3]. We then get a large folio > without !CONFIG_TRANSPARENT_HUGEPAGE. We can identify such non-folio (but compound) things by looking at PG_large_rmappable IIRC. -- Cheers, David