From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 171564A2A45 for ; Wed, 30 Sep 2026 11:43:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790768595; cv=none; b=eYLj0r0XYSi1IwOukeZQX0Uh0t73sG/Cg5Yfxuf9ASKTkuK3gz4BapCF06OAmWxOkRfxK2588VXzhXnHRtSTZTGLsaXWXFxLA4CLe3NbJRudX3FcxyKoXICzJWfT8E6L9Z6aiNPcP/z+oHUA91O5glixzPV4eWkABTkJRQPiybY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790768595; c=relaxed/simple; bh=79Jj0Bo7e+myNWt4D66xSn9KzWKtqNWAy4zt6NKZyQY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lmkDYsr61xwTf4jg/gqZRAo/E7qYuI23jd1eB9RABX5/yeywHgmnZFwYtuZu4IHDJ1hwbPri8OEfdps++z16+GOFTFgZlYiut95zk0iK/0zMWEThvd1qK8ACmDioz6uK8bX/+iLb60M9yk6+GGK8824SnGPKq0MluWKgre/09vI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UEqFEIN1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UEqFEIN1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3F051F000FF; Wed, 30 Sep 2026 11:43:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790768591; bh=9uMVOqMiTX1K2XJQJxXE/LwrK8qNT7KXfojMzsVrx8U=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=UEqFEIN12S69RdNlJmEU6fp0nKhSRNYo2596rxvjxQjmx2chUXZZo9T5Kr7lEEHGq d53074fabPnHx0Ed7wzeOZvSrzDEhKFOeMprzqQxseYpQ8SM7G8hq5VL9Eqc3Q5NEz ZUuZGVoVk1oYCpHTte4evrGtrM6DvnkAiuTfQWIfuyHETHInxUkKBPYAfYsbQHrJg3 WZqR2SBTQTSK+VdsJaAThusyW1cmH2rKwTuvE49eqDpsoviY9EFUc1e1GJnZCOb9l9 cXXviEcuLrkC6xBcgysrrfRB8GhwEtKQFh6CKxR8Ft2+934XQpBCsTmMG9PsH8dQGG iQnFD6ZxPIHgA== Message-ID: <7d120555-0c31-474f-893b-e5ee3466ead4@kernel.org> Date: Wed, 30 Sep 2026 13:43:05 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/mlock: fix zero-length request normalization and integer overflows To: =?UTF-8?B?67CV7YOc7ISgL+y7tO2TqO2EsMK3QUntlZnrtoA=?= , "Lorenzo Stoakes (ARM)" Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , Michal Hocko , Mike Rapoport , Suren Baghdasaryan , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <179066531783.50175.13377521828379196177@dgu.ac.kr> <3a95d0e5-7969-4b0d-988a-ead62b06b6f5@kernel.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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 9/29/26 11:39, 박태선/컴퓨터·AI학부 wrote: > Understood, and thank you for the feedback. > > I sincerely apologize for the poor code quality and flawed helper > design. I will be much more careful with commenting and ensure future > contributions strictly adhere to kernel guidelines. > > I will drop this patch. > > For David's question regarding reproducers and user-visible issues, in > case it is helpful if the core team addresses this later, > here is what is observed from a small test program wrote checking > /proc/self/smaps on an unpatched kernel: > > $ ./test_mlock > mlock(p, -1UL) : ret=0, locked=0 (silent success without actually locking) > mlock(p + 5, 0) : ret=0, locked=1 (0-length request falsely locks 4KB page) > munlock(p + 5, 0) : ret=0, locked=0 (0-length request falsely unlocks 4KB page) > > Thank you all for your time and the review. The CI seems to complain about test failures: # --------------------------------------------- # running sudo -u nobody sh -c ./on-fault-limit # --------------------------------------------- # TAP version 13 # 1..1 # ok 1 The map failed respecting mlock limits # # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 # [PASS] ok 1 sudo -u nobody sh -c ./on-fault-limit # --------------------------- # running ./mlock-random-test # --------------------------- # TAP version 13 # 1..2 # ok 1 test_mlock_within_limit # Bail out! mlock2() succeeds? on 0x7ffff7d2a010(393216) mlock0x7ffff7d44a72(278478) # # Planned tests != run tests (2 != 1) # # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0 # [FAIL] not ok 2 mlock-random-test # exit=1 So is this patch doing more harm than good? -- Cheers, David