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imf10.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=WWtBNl6z; spf=pass (imf10.hostedemail.com: domain of vbabka@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=vbabka@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1776433025; a=rsa-sha256; cv=none; b=7MYq7vi8EkMcmYcYkPGbrxggIdc8CSexWgmbQsZAEv1cmgdozdBeAbMGzc63GehOnaBG9i GIAh/oHhfkfJOpKmPXhogeX9uCq98mKD9utzixvhG4QomJI3IKJ9k9PT34q79pXLqfpqLF F89iIsq1UR7Zddgn7wQdlwVk9mp4Vm0= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id CE9EF6012A; Fri, 17 Apr 2026 13:37:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D23ABC19425; Fri, 17 Apr 2026 13:37:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776433024; bh=bLtdG6vevXUfno77DQCP6rd4j5CNBbChyvGTd2cZBb8=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=WWtBNl6zz4PCRKe1EfzhRc1ltfJAaguYJh2j5+vbHMsP15TfqYUbyrHVChpj2mPYh tzHjLWzKf4qGmLe0DVlJW5GcP15g3vMPXOr5acwCXIMrh9L23yxr26Bq5MYA5qM9/u rP5Ks+3mdYPDOu8HO2McAJr/sgHCToiFxYjQZG5pOQt4Qt7sx/efo5WY59wYunlxZz VSGgEWw3O0HPKZScaeVBH04hyIH086BbOn8e5oEXdxkX7DNbKcuqRJ+7tNVrfDbTCi 3cG/PUGAlH79glm0ieLvc/xjmTj5MsGnc/QL+MpHJghvdzNfRmbyNymvB6596Dcmzy PMQ1GPO1obFlw== Message-ID: Date: Fri, 17 Apr 2026 15:36:59 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: prepare anon_vma before swapin rmap Content-Language: en-US To: Matthew Wilcox , "David Hildenbrand (Arm)" Cc: ZhengYuan Huang , akpm@linux-foundation.org, ljs@kernel.org, Liam.Howlett@oracle.com, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, baijiaju1990@gmail.com, r33s3n6@gmail.com, zzzccc427@gmail.com References: <20260417011606.1089985-1-gality369@gmail.com> <66f67e51-819b-4c60-9f61-170db32362a2@kernel.org> From: "Vlastimil Babka (SUSE)" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 9npxt4tz3wzt9xawsqi8rax4gon9wwty X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 652D7C0002 X-HE-Tag: 1776433025-132886 X-HE-Meta: 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 WnvuuiN3 78jVTw73F1c5tg9bablB60n4IB/HhH4jX38174We7d3XXrGHvMutQqDk4QmskLwm1DiipHODnpZ3md6630cG7vdOTCAKBF0/oNh6pnMqD3fbjHniXY7+D+Rk0V+V7QSZEgynvTohuHc5+DNpy4BXBS6iO455QUZVUNfASOIUMGVxz3D3wBZLYfO3wd+hmqVRADhV9sfkKbm2YfOzyelRH5q3qQdbFXrmREU/RYSV/K0x/ERbsXRb5ZGDvjyfwz/Hda7MBmJQfPq0aLnisu97Jt84WXA6v9sKiIwUMblf2D7GU8AVQjAVy7LcnA6WsGNRpJS+Cj6hnNrj921ATxs3fTt+cr9Z79kyLuKqzpLP+xG7jbchJe3TLB9cOZtFnB2y0nOdv7YD4lXhp5D4= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/17/26 15:03, Matthew Wilcox wrote: > On Fri, Apr 17, 2026 at 01:57:59PM +0200, David Hildenbrand (Arm) wrote: >> On 4/17/26 12:53, David Hildenbrand (Arm) wrote: >> > On 4/17/26 03:16, ZhengYuan Huang wrote: >> >> [BUG] >> >> madvise(MADV_HWPOISON) can fault a swap entry back in through >> >> get_user_pages_fast() and hit: > ... >> >> I can reproduce this issue deterministically on v6.18, but I have not >> >> been able to reproduce it with the same setup on next-20260415. >> >> Just speculating, we had >> >> commit 3b617fd3d317bf9dd7e2c233e56eafef05734c9d >> Author: Lorenzo Stoakes >> Date: Mon Jan 5 20:11:49 2026 +0000 >> >> mm/vma: enforce VMA fork limit on unfaulted,faulted mremap merge too >> >> Go into v6.19. >> >> Maybe there was a scenario where we could have lost vma->anon_vma during >> a merge, resulting in a swapped page in an anon_vma. >> >> If this cannot be reproduced on 6.19+,there is nothing to worry about. > > ... except that 6.18 is LTS so we need a fix for that kernel version. It's there: https://kernel.dance/#3b617fd3d317bf9dd7e2c233e56eafef05734c9d > And maybe 6.12 as well (a373baed5a9d went into 6.9, so no need to > go further back than that) Not there (yet?) but it was tagged stable.