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 B9DCE606A31A for ; Tue, 27 Oct 2026 00:12:18 +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=VDt2TuLa; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=HRjv44oZ 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=hOt9i3fWrCvkhLM2HLoloHasQR3qmOkD8911902uNT4=; b=VDt2TuLafoxb3vIsfIu++BCGYc qU6NfYf0psJIxF4jOpzSGzurJalzQLbjkaNtRsyEunADW/m7k8XK5CVdUgAhO3PV16QzH2hd3AwTG P1qbJLCu+23BZlGgJfN6X+xzia6sy0qLsy6ucqvZ+KELaRWpThGz2bm+pg7IlRPg+MLC4TP8qHr9l WcjOvA99nvThnPRTOGU/RIYLVfjTegTd7ogASTgxew/AQthtQBjdGrRDXUUKkcZIqRCz0/AvTu4et Tx8wbVNkbcTh3GbK86WUuvpsQDSD5EXrT6Vku6aDXVpDh7nzDRdpamTiMqHIOc03Y5ZTL0c9p8zTk CYtmNa3w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUna-00000003UgH-1ttI; Tue, 27 Oct 2026 00:12:18 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUnZ-00000003UfW-2jvV for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:12:17 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 1426B601F9; Tue, 27 Oct 2026 00:12:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1066C1F01825; Tue, 27 Oct 2026 00:12:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793059936; bh=hOt9i3fWrCvkhLM2HLoloHasQR3qmOkD8911902uNT4=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=HRjv44oZj+AaychSTycZqoFxmxnPiaNJrfKXXjWbP5N/i3a2CxrktuS2DUb4L/RDj ApBt80Z5xT79bRozCtIh5rYcUom/ln40Q77g2Kas5woJPLF+25jYSidiKDt40n6avr p2u/lDt1uhWCecAFVbAAkXAjS5zBVQQURNrVTQOVMvndvkHSy7dyb8PKLDc44vNTIp or3wkvJGPgVQ5/CHVWhQeV3Mp+2ovFuCEjquobNgS/8ba26j9JaxYg1rSWA7bAmhNC bbaVvxBVuXSEPzjDqihZPj0XeK799FvzdpWyZG6HZygc9tm5u/dsDPk5SK3YIm2SYr QSd/zIt25O3rw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 04/46] mm/memfd: make f_pos accesses atomic 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, "Josef Bacik" In-Reply-To: <20261027-fixes_core-v1-4-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-4-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:12:13 +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: Josef Bacik >=20 > Commit 9c225f2655e3 ("vfs: atomic f_pos accesses as per POSIX") made > read(), write() and lseek() on a shared open file description of a regular > file serialize on ->f_pos_lock. The flag that asks for it, > FMODE_ATOMIC_POS, is set in do_dentry_open(). A memfd is a regular file > too, but its struct file comes from alloc_file_pseudo() and never passes > through do_dentry_open(), so it does not get the flag: >=20 > CPU0 CPU1 > write(memfd, "a", 1) write(memfd, "b", 1) > pos =3D file->f_pos (=3D 0) > pos =3D file->f_pos (=3D 0) > vfs_write(..., &pos) > vfs_write(..., &pos) > [ ... ] > Fixes: 9183df25fe7b ("shm: add memfd_create() syscall") > Cc: stable@vger.kernel.org > Signed-off-by: Josef Bacik > [ david: minor description tweaks ] > 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=3D4