From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793358666; b=ONJBdahzKnsccXn1LOJiV1DxCu4EGe0vPUkt/lC0lXdK0kQb8KE/T6OwYruLPVTbsIWt RY1SVS/ZxkVREbJXlaAhZUwm8OAaOu2RvS+7+RDUjM/ngRwG+CqT2q2qySrFhk0/Pu6av RKO3mzhAqb9K/XCljLaSxLxdoRpblPtx247I79D9Fz2mtQZLXk8ID9kAGQ/u1o/UG9YwJ 5YLPBnDMxOxJ1A9FflhMWIlnJsRbbTcpE8q1r4mZuBmb9SKdbgtvfxbk/sSQfkghZwbIK tMXsofJScYRE24l/Rg1t+zAArvWXjkvSWBURgMP2GdP8rP9D+mzsSGOdsN8f722YViw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793358666; h=Received:DKIM-Signature:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:Content-Language:Autocrypt:In-Reply-To: Content-Type:Content-Transfer-Encoding; bh=e5NnHqFGh2WLk8KpW0BJvN7IH3ve0Yj4mZZ8fp9OtsI=; b=d194eKl63+1mvCBqx2nRK/XeAoeYqr56GT6BTFmR3Hdje82sVvxl6qw8qFeEBAPTwzIn G9d26eP410XP3dnzlWaV9IG8OK0c6fckVkoO7E05nXjLowheXMzMyxD3sxK5K65ovCex0 3gdpTQ70QC0vd0oXRIqVeznWxLjUhvgUSVIydTw7Vvo4J9ZIciIVGvqwRJP34jr/g+Bz1 Mx9nex85g5kAiZL3ydbxo60yhmIcS7N3aEC/sXY3pq3ZZoHRHWhdmddyh+mBBwvu/gLkC KB96VVwfRPnAqeF1h8nheIDm9N32jmzWtLQatKf3ormdm6yv8uAOFJQbYl+68/Ogrig== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ewkqjIeb; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB8CD606A321; Fri, 30 Oct 2026 11:11:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ewkqjIeb Received: by smtp.kernel.org (Postfix) with ESMTPSA id 22FC11F000C1; Fri, 30 Oct 2026 11:10:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793358665; bh=e5NnHqFGh2WLk8KpW0BJvN7IH3ve0Yj4mZZ8fp9OtsI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=ewkqjIebBvhym6IB3Ksl7IZW4E3WWrG+/4yOGfUUwfsfHMqgAdiGfPsLito4NMzH+ 3X5GTmTwRVzbBuN0IMwDqw+qwS5ZG1TkZy22Bl6SI2a2ruWcosBrFpeUBZwQ1+X86r 2XsLssw2rnRioIhlsH3cexrza2qXr4bBiLO7ocs8u3A+E/DxolzLiaKG/WTEJdrZmV j3bSQu7F+PpI5upb84fHqRT4ETg6Pm/arVNg449Goy2wT41T8MsfIsurdfVxOe8Qwv dw++8VuLquwqT4MD8BXS6SL+v+RwX048NJm6rMxUecQ/wWmEsk2BQT0mxJGwf0odE4 9x6mq7eusSUaw== Message-ID: Date: Fri, 30 Oct 2026 12:10:47 +0100 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 14/47] mm/huge_memory: fix zapping migration entries for device-private THPs To: "Gregory Price (Meta)" Cc: Andrew Morton , Johannes Weiner , Michal Hocko , Qi Zheng , Shakeel Butt , Lorenzo Stoakes , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Kees Cook , Peter Zijlstra , Jann Horn , Pedro Falcato , Hugh Dickins , Pasha Tatashin , Pratyush Yadav , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , Harry Yoo , Alistair Popple , Nico Pache , Ryan Roberts , Dev Jain , Usama Arif , Kiryl Shutsemau , Matthew Brost , John Hubbard , Peter Xu , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Oscar Salvador , Minchan Kim , Muchun Song , Xu Xin , Chengming Zhou , Chris Li , Kemeng Shi , Nhat Pham , Youngjun Park , Joshua Hahn , Rakie Kim , Ying Huang , Jason Gunthorpe , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, Chris Mason , stable@vger.kernel.org References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> <20261029-fixes_core-v2-14-a64ce7f83abb@kernel.org> <179331304801.2127828.6570375349219520262.b4-reply@b4> 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: <179331304801.2127828.6570375349219520262.b4-reply@b4> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/29/26 23:30, Gregory Price (Meta) wrote: > On 2026-10-29 21:33 +0100, David Hildenbrand (Arm) wrote: >> From: Chris Mason >> >> A PMD migration entry can refer to a device-private folio. >> zap_huge_pmd_folio() checks the folio type instead of the entry type, >> so it treats such a migration entry as a device-private entry. >> >> Installing the migration entry already removed the reverse mapping and >> dropped the mapping reference. Zapping it must not repeat those >> operations. Concurrent MADV_DONTNEED during migration back to system >> memory can trigger this. >> >> Check the PMD entry type using pmd_is_device_private_entry(). >> >> Fix generated by an LLM and sent by Chris Mason in private. >> >> Fixes: 368076f52ebe ("mm/huge_memory: add device-private THP support to PMD operations") >> Cc: stable@vger.kernel.org >> Signed-off-by: Chris Mason >> [ david: simplify description ] >> Signed-off-by: David Hildenbrand (Arm) > > One note below, but it's not a holdup. > > Reviewed-by: Gregory Price (Meta) > >> + const bool is_device_private = !is_present && pmd_is_device_private_entry(pmdval); > > pmd_is_device_private_entry() already returns false for a present > pmdval - so !is_present is redundant. If there was a reason to open > code this, then keep it, but otherwise you could drop it. Ah, softleaf_from_pmd() takes care of that. Yes, let me drop the is_present check. (I'll double check that both are guaranteed to be consistent; but otherwise we might have a bug already) -- Cheers, David