From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 67D54606B5CD for ; Tue, 27 Oct 2026 20:25:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=Mc83FUFA Received: by kanga.kvack.org (Postfix) id 5B2A36B08D4; Tue, 27 Oct 2026 16:25:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 563166B08D5; Tue, 27 Oct 2026 16:25:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4529C6B08D6; Tue, 27 Oct 2026 16:25:29 -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 226456B08D4 for ; Tue, 27 Oct 2026 16:25:29 -0400 (EDT) Received: from smtpin14.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay04.hostedemail.com (Postfix) with ESMTP id A102F1A0AB6 for ; Tue, 27 Oct 2026 20:25:28 +0000 (UTC) X-FDA: 85369536336.14.C19AB86 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf06.hostedemail.com (Postfix) with ESMTP id E5330180005 for ; Tue, 27 Oct 2026 20:25:26 +0000 (UTC) Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Mc83FUFA; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of harry@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=harry@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793132727; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=FHMTsBnJMpXJNOaP415fipWiMQQwfvRW5x3lZ/lRcHU=; b=HzWu1hHqatK2fj1BliwagYXTO1K2nOZeppv11bElMOnzl44Ba/mdfailbK7GNFQJDjZ5sb WWcvl7FA9BCG3NWfdSiAAjjBwqYoV7JocWkgxdJ5AJb7jAjfuKnYm2F1BMnLSdz9cUwc03 72CLZiynqcu+PIXyKrO6QPb6t81pNJU= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=Mc83FUFA; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf06.hostedemail.com: domain of harry@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=harry@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793132727; b=X6rXMEt8A8VeO1OiCBHuj/5ydaPxTTdgXGOJV/XCmD2R1EsNVhe84j2L3+509cTzQRz4PF RrpDa4AtU6RYioBeVmnB8g5dsYI7YAMlI1RRVeRE3VNapkFC0P+KUGl5cBCxdkg1x8uyEx 82+jHRSbfoUUtfjuDjjA4yJOOraziTU= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 2DDF043370; Tue, 27 Oct 2026 20:25:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 758541F01340; Tue, 27 Oct 2026 20:25:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793132726; bh=FHMTsBnJMpXJNOaP415fipWiMQQwfvRW5x3lZ/lRcHU=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Mc83FUFATMQPouVzjUJeRj3mhiIcUvrA+Erhg5Hh0lTW3qwPysmiXYCN/sY2USdpd VQEeiyXwH3fAYJ+vI5Uk4lbY0OCURgOg/lZzGCGvnESQZo62rEREpGK+Ywua1pC7/p qLtQrl57LVvD3FOguw5Ccq1ddGp/nxRV2WelM6luaRwZ2gItpGPc55R3kKd/uEtYE3 F962dZ5NVZdLD83zdZJ57akrnRFkaxt1wSO3UiU8UVhqMNQKVzwdHfbh6D07tWcFW0 uvnXMmSet+gq+ZP42latzKtvPeBblPMlc6bL70NhuTjijHHpcfEiVBaUcHP26dtgTY lDs1oWuY01RLQ== Date: Tue, 27 Oct 2026 20:25:24 +0000 From: Harry Yoo To: "David Hildenbrand (Arm)" Cc: 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 , "Matthew Wilcox (Oracle)" , Jan Kara , Zi Yan , Lance Yang , Rik van Riel , 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 , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org, Josef Bacik Subject: Re: [PATCH 09/46] mm/rmap: handle device-exclusive entries in folio_referenced_one() Message-ID: References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-9-6f74bec9a5bb@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261027-fixes_core-v1-9-6f74bec9a5bb@kernel.org> X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: E5330180005 X-Stat-Signature: t16ikof6khrg88mz4yqs4n3a9qke48s4 X-Spam-Status: No, score=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793132726-445078 X-HE-Meta: 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 hpkFhxq7 15fA35Ew2XpW/TRyPnWbQXvbkJDu9SG43B63TFdCvLmDNI4a5hcOda7ykFVFF+0OHHKT+oL+klq4eE74F52vQTzhltHia5DoiL5gP6MayCk+242zri3yqZeD49d72CKe46drsr+xtjdoNP0En5OIE5NxGK1aJn06CQMXD0borDDa3nhaB4e5a1gjBLzMaO+3fRir1NhFknlIgITk9sSuavyHTg1ptFu1TFxQGulNAutSe9zaR4Y4ySVJ/9G9rIqyZetkAmDPbpVgG7jwbQtmoMy99ECArn/jC1/IsxfXv2hDa+8Pv2l1/+5jIfUyUeiL5tLCopgcdAhaPnMpT/mqN5nFcxtkdEM/rT8Vft55CDiB1nWmatomglvp9xhd41GQTJCDVebG2UM287/4wIKXA9mCk3Lc9axH8SqyrIHQAJKNQOIwg3T0U/cVVii2exCH6zh2AYFk7chrilzk= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Oct 27, 2026 at 12:17:29AM +0100, David Hildenbrand (Arm) wrote: > page_vma_mapped_walk() can return non-present device-exclusive entries, > but folio_referenced_one() passes them to PTE young-bit accessors that > require present PTEs. > > We must neither call clear_flush_young_ptes_notify() nor > folio_pte_batch() with non-present entries. For example, clearing the > young bit on non-present PTEs can corrupt the entry: on arm64 > PTE_AF overlaps the swap type, so clearing it turns a device-exclusive > entry into an ordinary swap entry. > > folio_pte_batch() will VM_WARN_ON_FOLIO. > > Apply the same approach as the previous fixes to e.g., damon_ptep_mkold(): > treat these entries as old from the CPU's perspective and obtain their > young state through the MMU notifier. > > Skip PTE batching and MGLRU look-around for non-present entries, and > don't modify non-present PTEs. > > Fixes: b756a3b5e7ea ("mm: device exclusive memory access") > Reviewed-by: Lorenzo Stoakes (ARM) > Cc: stable@vger.kernel.org > Reported-by: Josef Bacik > Signed-off-by: David Hildenbrand (Arm) > --- Looks good to me, Reviewed-by: Harry Yoo (Meta) -- Cheers, Harry / Hyeonggon