From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 92E3BCD3436 for ; Fri, 8 May 2026 10:51:42 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id E3E146B013A; Fri, 8 May 2026 06:51:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E151B6B013C; Fri, 8 May 2026 06:51:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D2B716B013D; Fri, 8 May 2026 06:51:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id BFFBB6B013A for ; Fri, 8 May 2026 06:51:41 -0400 (EDT) Received: from smtpin21.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 6D58B1C160F for ; Fri, 8 May 2026 10:51:41 +0000 (UTC) X-FDA: 84743936802.21.69F656D Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf01.hostedemail.com (Postfix) with ESMTP id 8E9AA40005 for ; Fri, 8 May 2026 10:51:39 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="hFyUY/4R"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1778237499; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=wGGhdmtD4t8YuerKBjceRuz77LrqZ+pIjvP6tCg1isA=; b=G5EiAaecdmUMoajvNV0CiLiSHYiE7NNQjjr5zKyhR/npzPNDb1COYGjVN0Lg+Uub4DLK/y XciwUATwtw/e98kTW4/3BfjPGIKla3uUezjf7GWfW1qpx8V+PLGZy+iP2k9YbYD4HzT148 Ph9191kV6GNEi7a2PRe2TpR8E5mD1B0= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1778237499; a=rsa-sha256; cv=none; b=tJgC9L1zTcXa+aJJloNxUEfAlUHiSoTwUFNm6Nn5FT4M8Put1vjz5eYMKqPLyntI6fT5kV FE2IwLJ4/zwF3Ts+ZA2Tkm3lugpF3kYpRc/8npZFuXa85gMhtgEbSRotWER5UInPF+O0eR Oi5aHo/or7/iD9t1aC0e7Dn/8WmEx10= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="hFyUY/4R"; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf01.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 6156E40181; Fri, 8 May 2026 10:51:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6125AC2BCB0; Fri, 8 May 2026 10:51:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1778237498; bh=qCpEEfxXt+O2YalNOz8YFSPd7ea9aZm7SxUJ43Dltv4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=hFyUY/4RVuCp9PbaDxytWEEh5iyW1CSlyT8wIvpIfGE+c17XC4wEEtzslZWwYLIPK lngFKI70LiyK0+lA4OOoIvpfjpAtULpiL6HuAMJWS0REi3HtCWqJglVQSm4G8wrpGx X5BrVT0vHz5MUiDzsBEB6ZzWqVskqNqpamiHDQpbCMtmQLLM3/voRHlXN/OiuuXbAG R291+c13szL/G7sg10Cdllhc+46mqJ+Zh1alQ4NkIB41hRGiMsRVg+Bsvj1MLr4P7X 7/SB+xOG8ybgJb5B2J3X4ISSt29Lb/qYJo7pjmWRKULLsAeEUWxDDrs1MraCRaMFaD P8gNZl34eATiw== Message-ID: <32fc4c35-acdb-4202-8369-ac0fe00c5b86@kernel.org> Date: Fri, 8 May 2026 12:51:31 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] x86/mm: fix freeing of PMD-sized vmemmap pages To: Peter Zijlstra Cc: Dave Hansen , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , "Mike Rapoport (Microsoft)" , Jason Gunthorpe , Lu Baolu , Andrew Morton , Lance Yang , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org References: <20260429-vmemmap-v2-1-8dfcacffd877@kernel.org> <0c20d1e6-1a39-42c5-8c94-9bd2222fb6b3@kernel.org> <20260508092341.GP3126523@noisy.programming.kicks-ass.net> 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: <20260508092341.GP3126523@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 8E9AA40005 X-Rspamd-Server: rspam04 X-Stat-Signature: r1w6wmswk6f75qh3h7sr9n353hwgs6k1 X-HE-Tag: 1778237499-428496 X-HE-Meta: U2FsdGVkX199Ib5Vuw4xx20UvfUST3cWyHB6pw1RTmykwmdoNo4mKkbArIwCV/Vazrln/ksy7hH24nYsFwnMv+mBXDhUGAtgVLiPngzrMTOay4kOkGNYr0wq8jBtz+xiPzZLWpZ5ZhlL6QB3CAslAuIlumdokmQourLlZHF/6koUtD+KUpHHVwDemPWyqp2n9Ae9nq73Urg92HUKPIdNo1vPofwz2n7FsD/MojokeFFhkgODfMC1QGzy8LMYl5dpaadPyMOlxhQLktFubj1goTo2lBPEwqWxCUXhhBaSG41D4pp2yAcaoCar2eB4LoM3I1kBdHAvRfpRtG8NezZjDoMl/+vl9edbWcrxWlJBaT2hF9FzkJ+q076mwK76r/o95rT6LgC3bJJyBGSAIygKD4qR36e6QvZ9rvugcm2iXK4reCVlsMZzb3sxqx3DujuhiPVc80zhECVGiPj+qx0mERv7JMJ2ixmZ3WzKfbOi4EAejvxF+Mc7DL350KIsIbP8E8PD7oI7HhxfQTIIyTP65yhcM+bs+g7GR2OQ4VnYEQEjdXHkBk9pwvF6OxHEb8Ckeutp6Uog94aHuwcJkp9ZXZ6lnX9nkKCJKT5dA8QBRYKKplUfeX6FoRNKAeEpVCnVfrFbETbaF4Z8L7bFkKQpva90FR9YwUsi/C7yl7TSoWKO4xpoIDYFUHGl6lkwW5gncnm0JD3FJmbkixQGCNQjh1lM0xLld1eD2nN4SYZlhYlyzN089yQ3A5Q6hbDQWdqyFf+9CWMAdTfmzdFgWAJIb8M2K+zV0H3u9qVND+yQEDEifzAQ+darUEW4qowFAchXnFY+dwE1UNU0aNfwnQpaPELvjq5pR6EyHkYHrkk3CHnulUvGx/TLQbK6A2o4bpXZqmeTBGb3rM4cSGUm8K7TKem/+gVusB8NKiB1oIGRDHXBdtUDTC+v8dWg2VjPre972tIVajtArpXaPEbjain 6oYsMhU/ KwhgS3wS2OBMoGoD54MDmyjZ0B+FEBzcElzYvnybI/E6kSSj+U6+UGtxgRQRffYWGOP8FMTClgaRupX68kHvISBjMAL5l9Va2GOdTtjGSJhLPymXyHDMdayZrYq4hjpclXmy6emN0zGdFskFSba+bQir0AbIrOOzRdYprlkdbUb1Hii6JyMS/euUiOF+Tau/O5NFON3cetRgJNs1UepWeNh4Pfx5OckuUvDHoTGCjFvdFOunPlFPIHvRGR/0pjT9cieu5GlGvfv7glTqka9V8mc6cxzpY1pX4z60o Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 5/8/26 11:23, Peter Zijlstra wrote: > On Fri, May 08, 2026 at 11:19:26AM +0200, David Hildenbrand (Arm) wrote: >> On 4/29/26 12:49, David Hildenbrand (Arm) wrote: >>> In commit bf9e4e30f353 ("x86/mm: use pagetable_free()"), we switched >>> from freeing non-boot page tables through __free_pages() to >>> pagetable_free(). >>> >>> However, the function is also called to free vmemmap pages. >>> >>> Given that vmemmap pages are not page tables, already the page_ptdesc(page) >>> is wrong. But worse, pagetable_free() calls >>> >>> __free_pages(page, compound_order(page)); >>> >>> As vmemmap pages are not compound pages (see vmemmap_alloc_block()) -- >>> except for HVO, which doesn't apply here -- we will only free the first >>> page when freeing a PMD-sized vmemmap page, leaking the other ones. >>> >>> Fix it by properly decoupling pagetable and vmemmap freeing. >>> free_pagetable() no longer has to mess with SECTION_INFO, as only the >>> vmemmap is marked like that in register_page_bootmem_memmap(). >>> >>> The indentation in remove_pmd_table() is messed up, let's fix that >>> while touching it. >>> >>> Note that we'll try to get rid of that bootmem info handling soon. For >>> now, we'll handle it similar to free_pagetable(), just avoiding the >>> ifdef. >>> >>> Tested-by: Lance Yang >>> Acked-by: Mike Rapoport (Microsoft) >>> Fixes: bf9e4e30f353 ("x86/mm: use pagetable_free()") >>> Cc: stable@vger.kernel.org >>> Signed-off-by: David Hildenbrand (Arm) >>> --- >>> Reproduced and tested with a simple VM with a virtio-mem device, >>> repeatedly adding and removing memory. >>> >>> Found by code inspection while working on bootmem_info removal. >>> --- >> >> @x86 maintainers, do you want to take this through your tree or should we merge >> this through the MM tree? >> >> I have another MM series coming up that will touch this code (no fixes, though). > > I'm thinking this should go in rather more urgent, yes? Yes, please :) -- Cheers, David