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=1793009071; b=BMuyWgkwFKQPMPY1lb2z455nhwB3WAGy5AU62eaTYFXDP8F4/G0gxCdeOZh5ZBvRwL9T zr/0lma7xckQNxUyN+08cezjckirX8PO4N2M86FCTzVt3bi+6Y17jmiPiuOVMHK5/oB9T fGGkprBxzOYICuzwFrP4oHMNUD+VPRtYvVIgLT4rR/cWJWZLxQ1SHNO6UT7ULi2Nhxsjz 8gmveIa33sz4RQYa3aTFzZet5VwUPXnrfXarRoJ37QI+OOIfKcU5KtZJF6yeoaS2rzqlZ x9eHPZc/MdGuFIq9bg7D2bFtM+zG8qnkXUHZexBQazAfrlX09wfdQFDUnI+KRy6+Mbg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793009071; 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=PRfBqEtZY9vLSO/v1o7cinPO/v+UATyLQat9ERvQExs=; b=4RnmN6iu0jgrjmjOguMupxFIU2LG1zyzpVrnu4exrCD5EyYWlw+rF88RxQhUtQ8igtNg eYsctVCUW8RBjQfwEwRB+cTYAC2SGQ/xs4lOS/iV0aNF7MdM9RnEZPTUNk0qvQe7RXf2V lYXZ4lxE8OAfiOTimY9IfDtzzqN7rMm/v4SW9bZkuOgur8to+mUwAWAA2YHi/QmDGYr1Q CO+1/hvrKw1QGd2rMMtptf+7vEz3sc1IzltchUjXMvSY42Ed2fbelZTXL2kN/cpXmsapr EXxo9WDqxT/bSU3S/DgZCCPLhbs438QSOp9TNkHHZVVZR75pL+8Nx7UBTMftrPlym5A== 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=CintjnD4; 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 AA9D6606A331; Mon, 26 Oct 2026 10:04:30 +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=CintjnD4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id B36B01F01828; Mon, 26 Oct 2026 10:04:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793009070; bh=PRfBqEtZY9vLSO/v1o7cinPO/v+UATyLQat9ERvQExs=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=CintjnD4Et7gXs29ZrsCkod5VJq2bgilI/ipEqW97jU/PCLADSUO2wLwnPcyLl1hB NraxPlpqgH76NLpNh9tq4QpPKO/RnpKUO7lN8i0e/NPBvfaWIliCqxAecCuPZMoE6W b0yAiOf05Eg3CzC8NBbutl7l7OQbglYh5lDCaeRaw309XoDIJVnVDoYPgHKbekqnR5 aWgW6GhEm7LvqD+NASSvfBhSuatTJ8THAJ8OURJVGdiQWPWHHas52cNXbNQFrk66CF 1UNoUibOuxvARe5xG+1QdAFEysnJnwhl/T7w6ae4Z7Iutb8mle1Wiy6RQh9GZiJNzI dSM3s1M6DpjCA== Message-ID: <44405019-7494-446a-86b4-05b2ac03f768@kernel.org> Date: Mon, 26 Oct 2026 11:04:23 +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] fs/proc/task_mmu: fix missed VMAs when reading /proc/PID/maps and friends To: "Jose A. Perez de Azpillaga" , Andrew Morton , "Liam R. Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Pedro Falcato , Suren Baghdasaryan , Shakeel Butt Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org References: <20261025-per_vma_maps-v1-1-c4eec45b9387@kernel.org> <533c4ef7-e008-4439-be40-1aa2a074dfd8@gmail.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: <533c4ef7-e008-4439-be40-1aa2a074dfd8@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/25/26 20:01, Jose A. Perez de Azpillaga wrote: > On 10/25/26 11:43 AM, David Hildenbrand (Arm) wrote: > [snip] > >> Fixes: 5631da56c9a8 ("fs/proc/task_mmu: read proc/pid/maps under per-vma lock") >> Fixes: ea3085dd7a4e ("fs/proc/task_mmu: read proc/pid/{smaps|numa_maps} under per-vma lock") >> Fixes: 0e985559d72a ("proc/task_mmu: read proc/pid/smaps_rollup under per-vma lock") > > PROCMAP_QUERY does the same fresh lookup, shouldn't d9d1c2d81797 > ("fs/proc/task_mmu: execute PROCMAP_QUERY ioctl under per-vma locks") be > here as well? (commit tracked down by an LLM) Hm, very likely I missed that. So yeah, let's just add it. I assume it won't matter much because 5631da56c9a8 is the oldest one either way. > > [snip] > >> There is the issue with seqcount overflows that Lorenzo is tackling. It >> probably interacts here as well? Likely, but that's an independent issue >> to resolve. > > the saved seq is reset on every m_start() and query, so a wrap would > need 2^31 write locks inside one read() or ioctl, I don't think it > matters in practice :) > > I tested it on x86_64 in qemu with KASAN, lockdep and DEBUG_VM on top of > mm-unstable, the maps holes I hit there are gone. Also, the code LGTM: > > Reviewed-by: Jose A. Perez de Azpillaga > Tested-by: Jose A. Perez de Azpillaga > Thanks for the review! -- Cheers, David