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=1794605977; b=wVJu4uciSNvLh/6OJPxy1ubrIGtbyjmrBJY99ArVQullAwGM8wft/Vgi1xV4cGg9hsFU g4JFbc8sO9kWD9eA/s0bZTw2yJawfXGzlI3KOgfqmBaNxBkku5+TEm/DBz05xXvBvfWJ3 vWz664SJ+k4HKsZgpNLUkGUfIW+8pLg3qjvLxHqwynMPTw90vKJoA9ieNNrM3M10FY/38 vr2MDKxPN5sO7EEIorKRVeXSz7OV81nvI1BtToTS9a2Dn78JZ1VQQ01rVHh032UPVG0U1 eDeFcLU9jjmYGCoHQTiU8Mw6ES2PDVCL9eQ7XeGMcgE9u30oFlJ36HLLY69fIr2ynIQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794605977; 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=HQYsjuLSgqmkYc+gxSurb8uN4B+g/9xyTOSp3ZLANuo=; b=VNhduAAquQ5JgpSniDYgACvQvJeKGTGw/RPzxdUFQs2JHS++VgI4KwWOV3D9e6MSq8My GNjcH6vRuljq7cZdHSHCLTAZ1nuwUX8BreqBY3lZ+avG3fHRwIKC1g2i3F6gyoglUGZw/ tecErnFNr97LQoWoWWRUotXByD32wz6XyImEf+wcUVX1RhEvPgDki17NFnjdVcyY3iTzs 6nyH0NIAQffZOdograZkorFgfvwaCv0urd6IVoiO/Ld5djhIMTTgf5EI2kTexgQvEBKo1 tCcv106Iq144+fADX+RqkkS4gjz6uQcyQNujaYXtxnYKZ1CtHb9OjOkxiK675yBtSfw== 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=cbvfpgu8; 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 9B17F606A32E; Fri, 13 Nov 2026 21:39:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cbvfpgu8 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70B0C1F000C6; Fri, 13 Nov 2026 21:39:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794605977; bh=HQYsjuLSgqmkYc+gxSurb8uN4B+g/9xyTOSp3ZLANuo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=cbvfpgu8tOow6Wv2h/7RSGys/vhrTWGQUnh4KqZ/MxLpfcdUf3D5uLQJDematIwO6 pF8ZFDoI5V9m6v0E2uv31piPTWg5RXcGhHOMnGB+I01f81xmVBupgzZAhOd1wnhrNW S9hFDCZ8T/veXtk3HWrex1bO4RiSQWcnyZWnwvE2hEuQIiziMaZL8uAjJVaIED0+dX 8meuP51dZrUS3Vzh9kCgbv2SscDfUdKlnVIslfTnnyoRorO6NK6HfpIJ7CuQZO8P84 WPetnx9aM+9b3QGtptr+vAsx7A4FMTZfolDdiM/+o0o+7Pgeat5j7DADWq6BOdsgh0 uZwK1kSfZhR9w== Message-ID: Date: Fri, 13 Nov 2026 22:39:30 +0100 X-Mailing-List: stable@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] mm/madvise: zap markers from guard regions To: "Lorenzo Stoakes (ARM)" Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Tal Zussman , stable@vger.kernel.org References: <20261113-disallow-uffd-guard-install-v2-1-9d0063c70542@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: 7bit >>> mm/madvise.c | 28 +++++++++++++++++++--------- >>> 1 file changed, 19 insertions(+), 9 deletions(-) >>> >>> diff --git a/mm/madvise.c b/mm/madvise.c >>> index 0214efd2a014..4f7728583207 100644 >>> --- a/mm/madvise.c >>> +++ b/mm/madvise.c >>> @@ -850,6 +850,19 @@ static int madvise_free_single_vma(struct madvise_behavior *madv_behavior) >>> return 0; >>> } >>> >>> +static void zap_range(struct madvise_behavior *madv_behavior, >>> + zap_flags_t flags) >> >> Two ... ;) But maybe it's consistent like that in the file, didn't check. > > I'm a bit exhausted, can you or Andrew just fix up whitespace like this on > application? > > It'll be easier when I have the VMA tree. Yeah, absolutely. I'll let Andrew pick this one. > >> >>> +{ >>> + const struct madvise_behavior_range *range = &madv_behavior->range; >>> + struct zap_details details = { >>> + .reclaim_pt = true, >>> + .zap_flags = flags, >>> + }; >>> + >>> + zap_vma_range_batched(madv_behavior->tlb, madv_behavior->vma, >>> + range->start, range->end - range->start, &details); >>> +} >>> + >>> /* >>> * Application no longer needs these pages. If the pages are dirty, >>> * it's OK to just throw them away. The app will be more careful about >>> @@ -872,13 +885,7 @@ static int madvise_free_single_vma(struct madvise_behavior *madv_behavior) >>> static long madvise_dontneed_single_vma(struct madvise_behavior *madv_behavior) >>> >>> { >>> - struct madvise_behavior_range *range = &madv_behavior->range; >>> - struct zap_details details = { >>> - .reclaim_pt = true, >>> - }; >>> - >>> - zap_vma_range_batched(madv_behavior->tlb, madv_behavior->vma, >>> - range->start, range->end - range->start, &details); >>> + zap_range(madv_behavior, 0); >>> return 0; >>> } >>> >>> @@ -1217,9 +1224,11 @@ static long madvise_guard_install(struct madvise_behavior *madv_behavior) >>> >>> /* >>> * OK some of the range have non-guard pages mapped, zap >>> - * them. This leaves existing guard pages in place. >>> + * them. This also drops any PTE markers in the range, >>> + * including existing guard markers, which we reinstall on >>> + * the next attempt. >>> */ >>> - zap_vma_range(vma, range->start, range->end - range->start); >>> + zap_range(madv_behavior, ZAP_FLAG_DROP_MARKER); >>> } >>> >>> /* >>> @@ -1845,6 +1854,7 @@ static bool madvise_batch_tlb_flush(int behavior) >>> case MADV_DONTNEED: >>> case MADV_DONTNEED_LOCKED: >>> case MADV_FREE: >>> + case MADV_GUARD_INSTALL: >> >> Huh why that change? Not spelled out above. > > It's just the established way madvise interacts with TLB maintenance. > > Anything that uses madv_behaviour->tlb has to return true here so > madvise_init_tlb() and madvise_finish_tlb() do the right thing. Ohhh, I see now. Acked-by: David Hildenbrand (Arm) -- Cheers, David