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 12E0EC5B56A for ; Tue, 11 Aug 2026 15:39:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 34EA66B00AD; Tue, 11 Aug 2026 11:39:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2FF7C6B00B8; Tue, 11 Aug 2026 11:39:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1EE226B00B9; Tue, 11 Aug 2026 11:39:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id E5F566B00AD for ; Tue, 11 Aug 2026 11:39:02 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 7BE14404C8 for ; Tue, 11 Aug 2026 15:39:02 +0000 (UTC) X-FDA: 85089396924.19.5E4F6EC Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf12.hostedemail.com (Postfix) with ESMTP id AD70240007 for ; Tue, 11 Aug 2026 15:39:00 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=RWQiad2L; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf12.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=1786462740; 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=vty8HoeDTr0Ll+bsIomYHFcGaBT3FmdH1oXuNYagVx8=; b=kcQraU1oI0gDwI0em3W28A3Rc5cngO0V6bBzL/bkMuq6JOR7BvaV1ox290Ix+prUNFXlBZ eOgub6U0GjisEHjpDNec1oXrB+yX9fFiB3E7/EC9nHgi9gmKEYT3s3Cd0dsk4KHTzxSWMy te3BaW6RySi2fojHk52wqjGUqFu2Id0= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=RWQiad2L; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf12.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1786462740; b=yQhiBxCCkTfFm4TEhAzjLL5N197ODjgwf7J9YYciKHil+OjeBA6EyXAzD0jlfTYKgJcA6e XgRHKlHyRm8Ppnx/nSmUDjDTFxRx1CBE4ehhIs4OQ1jjAndTdDsvwkXymLSAr0q9XozV0v j7EkHBcSr2n1IFFyo3sZ3yJQrZQ9RhI= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id CE01441E8E; Tue, 11 Aug 2026 15:38:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 332B31F000E9; Tue, 11 Aug 2026 15:38:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786462739; bh=vty8HoeDTr0Ll+bsIomYHFcGaBT3FmdH1oXuNYagVx8=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=RWQiad2LffBylWd986oIPwwUu+DA2UISu4R2DBDtCFwDvLnA948PxR/kEN5ijUfdO vblsE4BkCOLbZD6WPgKTjF9g1W+kxCIuBXwMXXSiYeLtJqwgkC2E9fJSrCBvD9OjFr CgGdLX1Kl+iNvlN2YQ1uv3y8C5+QtBDrs+cYm6ghLkF1bEPj7TuAWWFrcyFMsP7SW5 Z/TKXOJRv6s2QNLc9KBCeHj+WO4dnCcTmIsF7kM0Ymj3p84zv5VmOwaiyIbpopXkeg gmDPrTfiQ58RMuIExi8Z66vkKUSURJNYAGa3L9ScCyMYUr7DoS9CgnTmL5E6tA1IRQ zfTkT0M6U9dYg== Message-ID: <8c16339b-6050-4a5e-aa89-9f2f96e7dcb4@kernel.org> Date: Tue, 11 Aug 2026 17:38:50 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] mm: fail the fault on a malformed swap entry instead of retrying it To: Breno Leitao , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , Hugh Dickins , Baolin Wang , Peter Xu , Johannes Weiner , Yosry Ahmed , Chengming Zhou Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com References: <20260810-swap-v1-0-375ef0767206@debian.org> <20260810-swap-v1-3-375ef0767206@debian.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: <20260810-swap-v1-3-375ef0767206@debian.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: AD70240007 X-Stat-Signature: fujywpbmqneetzytfrmxa1it7remddqn X-Rspam-User: X-Rspamd-Server: rspam11 X-HE-Tag: 1786462740-194145 X-HE-Meta: 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 FeHJgXli QkdYLkf13bSDi4YCn3ahpLgFXylnC+j85ddfXD51J0Mpf9XcM7hV+9U8gyad5ZU9yAvXu5EAGM0DmFRh9LMj/f74C6MZfFmdXkw/SFDcHBLINTS44JnNFcl/xhV0Eusdcup/QlRhzRWltZsApeK/XwVbOkbM9838UMpBwK7us/uGWehKam9+5/jIZpTJbwUW5vmnCrOdPffvmu9LiB16aHqEjamhZJNU2QrW3MF5LF5Y2P9CLWmhUeRpwAPjUgnfdqzhcp+caTIyfnBUYZ5lA9yxzgabhh7qVwlB/ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/10/26 18:26, Breno Leitao wrote: > do_swap_page() returns 0 when get_swap_device() fails, which the fault > handler reads as "handled". For an entry that can never become valid > the retry takes the same fault again, so the thread spins until it is > killed. > > Return VM_FAULT_SIGBUS for a malformed entry, as the sibling arm > already does for an unrecognised non-swap entry. A NULL return still > means swapoff, which is still worth retrying. > > Signed-off-by: Breno Leitao > --- > mm/memory.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/memory.c b/mm/memory.c > index 4238778b66c42..2842cd976f1d3 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -4957,6 +4957,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) > /* Prevent swapoff from happening to us. */ > si = get_swap_device(entry); > if (IS_ERR_OR_NULL(si)) { > + /* A malformed entry never becomes valid, so don't retry it. */ > + if (IS_ERR(si)) > + ret = VM_FAULT_SIGBUS; > si = NULL; > goto out; Better update the comment above get_swap_device() to include "bad swap entries" as well. Best do that as part of patch #2. I didn't look too closely, but conceptually LGTM -- Cheers, David