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 4D90E606A31A for ; Tue, 27 Oct 2026 00:14:15 +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=dDlKQWVt; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FIt7QM+L 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=ynZeVp4GE9gMyAxS9d+MxTL5L2L0Jem+z5pMoQXOO9g=; b=dDlKQWVtm7lAxvhiF+9NwBFnBQ TkeSzqTli1D8P15y3RmpwVw84M3Qc/h2bmylqOPQzhfg5kwBXNr3ngk9Crp/evm5k4qk/65Ug9LZV oGuOvG4hVDk5A+sJgY44UMhUggpSbPpk+BS0Y6Wve7w+nD5BIQHc2PE5jeRVabSiayxzeHzjU6FYW YhZ6BOqFyOOrr/KpmvN5TFGqGNvhYByRqyIrMJXNhfY60J++qs+8qeMSV4DwzOxg/H+uG9oXcbyw8 7i5jD7iflhbUHJ07AmRW1FSgD6ZlPNwXwFfQufYgl0yDmD6/ODWpCSjN7vejyrnK7ictwqBXWrk0h EFOKcJlA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUpS-00000003WAG-493G; Tue, 27 Oct 2026 00:14:14 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUpR-00000003W8g-35xU for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:14:13 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 13A51600DA; Tue, 27 Oct 2026 00:14:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B2211F01825; Tue, 27 Oct 2026 00:14:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793060052; bh=ynZeVp4GE9gMyAxS9d+MxTL5L2L0Jem+z5pMoQXOO9g=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=FIt7QM+LtoZk/9BMUyqAGkEqusx4YtcgVhjZHuLbQmkAPmFpiKHoj50I5rfGlpTUB I/6yCj4jjbNg4pykPFfQk0rZ2IF2lljJtXWDOkmFls6j0GbQnSEEll/RcW7WW67y03 qMDPxlxH4NLZeeC4OI9nt5oRHqRef9ggF/dC554M9peo2dQY6WGEAcx73ubuNhcCTY VTRYZ2o90gMMhYOcnjUVKRAMUVWW3l+CrIHX5zJ5ulJCmJkhbSOdPo6u+x/K6NEp6X 8bpNgG24anMGUNmhGCJdidIRmTUtTwqZ+yTh2bwdl2B4QWpXN3+ji30NhkIeVcyFbJ eQVTNmGLEDqEg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 40/46] mm/ksm: check large swap-cache folios before mapping them 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, "Chris Mason" In-Reply-To: <20261027-fixes_core-v1-40-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-40-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:14:09 +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: > From: Chris Mason >=20 > KSM folios are always small, but their shared swap slots can be read > back as part of a large folio in the swap cache. ksm_might_need_to_copy() > skips large folios, so another process can map a page with an incompatible > anon_vma or page index. Reverse mapping then cannot find the new > mapping, preventing migration or reclaim. >=20 > Apply the same compatibility checks to large folios as to small ones. > Pass the page corresponding to the swap entry and copy only that page > when necessary. In do_swap_page()'s copy path, decrement only that slot's > swap count, because the source swap-cache folio can now be large. >=20 > Fix generated by an LLM and sent by Chris Mason in private. >=20 > Fixes: f1879e8a0c60 ("mm, swap: never bypass the swap cache even for SWP_= SYNCHRONOUS_IO") > Cc: stable@vger.kernel.org > Signed-off-by: Chris Mason > 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=3D40