From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FFF6606A31B for ; Tue, 27 Oct 2026 00:12:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=fLwD/b90; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Snsra9xJ DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=wQB69hSW6YziJlDqV1x6zqf96bbnGEi8649p3JF4lRE=; b=fLwD/b90onP5lWdUcvg3YIt/uY 0+yRV3Su9QdUTjUmCsDxP9MRkW7XQpL/Ko1QtXwTiTvO0so2607pTo5jyfnE3iceqKc4AOH3n0RCO iqYCcwE+2q3ZqW0uOnFTbXY2ZmIsjFb7Ys/Lta1fzty4STocrOGz/If3UlFCGM/iu8VKMUOO4lDWs 95AkU6bEpKTjPw/A7msd1RxQkhT6qFOTO4eMAtE2fVWZSDPi48awMUiFxm+J8nHZ0kmBZaQDFbdFO nM87kihdQz1zvrAQfUvX28atjNWpxk5Y9RN/7IzSEcDphwOZBVX9YNnRhxQsJ2f59gw4xnfKKatsu FIYIhr2A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUnw-00000003UxC-0WA8; Tue, 27 Oct 2026 00:12:40 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUnu-00000003Uvc-1tjG for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:12:38 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 3290840AA7; Tue, 27 Oct 2026 00:12:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80A421F01829; Tue, 27 Oct 2026 00:12:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793059958; bh=wQB69hSW6YziJlDqV1x6zqf96bbnGEi8649p3JF4lRE=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Snsra9xJ1+O3/DF+7WFjYEwCs2LyyyGS5aMUfqdcE5WZu5i4MEHaZCMlmpYijEWP7 xT75jKcxGJJgp7mRqDd2iIsMHmPWdIiatvTfNH/EJNNec5OfiRtF9FVNT821RJVUX9 +FqId3qMKY4BEWvaLPnwltadYxxuNcd59alwwDmkW/tl6aAtcyGNYOSj0CBx6wB5Vd ZKOOuQVpwvT1UVlb4cLd0Pv/XtY4lWyVds0v9sk9TtjYc+vMOy6ecwak84Ra6zNKDo ZbR6QQSWqFiWfApIJsbKmHgPb24KGmvYhCwnZdgBSEjo5DiiSbYTcCpVuLEqHo6RGn BqumG7tbVgqZA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 11/46] mm/huge_memory: properly handle refcounted PUD mappings on fork To: =?utf-8?b?RGF2aWQgSGlsZGVuYnJhbmQgKEFybSk=?= , "Andrew Morton" , "Johannes Weiner" , "Michal Hocko" , "Qi Zheng" , "Shakeel Butt" , "Lorenzo Stoakes" , "Kairui Song" , "Barry Song" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Baoquan He" , "Baolin Wang" , "Liam R. Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Kees Cook" , "Peter Zijlstra" , "Jann Horn" , "Pedro Falcato" , "Hugh Dickins" , "Pasha Tatashin" , "Pratyush Yadav" , =?utf-8?b?TWF0dGhldyBXaWxjb3ggKE9yYWNsZSk=?= , "Jan Kara" , "Zi Yan" , "Lance Yang" , "Rik van Riel" , "Harry Yoo" , "Alistair Popple" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Usama Arif" , "Kiryl Shutsemau" , "Matthew Brost" , "John Hubbard" , "Peter Xu" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Oscar Salvador" , "Minchan Kim" , "Muchun Song" , "Xu Xin" , "Chengming Zhou" , "Chris Li" , "Kemeng Shi" , "Nhat Pham" , "Youngjun Park" , "Gregory Price" , "Joshua Hahn" , "Rakie Kim" , "Ying Huang" , "Jason Gunthorpe" Cc: kexec@lists.infradead.org In-Reply-To: <20261027-fixes_core-v1-11-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-11-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:12:35 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > copy_huge_pud() copies device-DAX entries without taking a folio reference > or updating mapcounts and the child's RSS. >=20 > For example, MADV_GUARD_INSTALL sets VM_MAYBE_GUARD on a device-DAX VMA, > forcing copy_page_range() to traverse the whole VMA on fork. Any remaining > huge PUDs are then copied without accounting for the new mappings. > Unmapping them in the child decrements accounting that was never added. >=20 > Use vm_normal_page_pud() to identify refcounted mappings. Take a folio > reference and add the child's PUD rmap and RSS accounting before installi= ng > the copied entry. Pass src and dst VMAs consistently instead of src and > dst MM. Move the TODO. >=20 > Fixes: aed877c2b4257 ("device/dax: properly refcount device dax pages whe= n mapping") > Cc: stable@vger.kernel.org > Signed-off-by: David Hildenbrand (Arm) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261027-fixes_core= -v1-0-6f74bec9a5bb@kernel.org?part=3D11