From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=96.67.55.147 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793066885; b=4XSGot1qx1GDufoafcirAs8CinD6cOLd1HNsjgmgEmaXkMqoXVoP9VZzxdbkVjKE9cDZ r/rSdXplI39zt+T3E9Z0XpcJXz7m9PJbuovGp5VsvIiwGje0t3RzcJw47ewBXvcXDUmQN Sez40m6SdiHi07ndLbtdG6ESEIUdKfQVk/NtKztvVaO7O6z0CYHvKHEI+2xGM1eScEHdu YzsFMXCZXIs/Sb9vRJL0JqNDrIj71P8GdqkrsmC/Ppe+AWeMTsUVQofIkj9mGaa1Q5EeC jOFRp5uKaByLUUjMLQuI8icmM1lkhBgoW6h+1E97oYnZCeBTK+UsjeBwUL9S5ZgYJrA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793066885; h=DMARC-Filter:DKIM-Signature:Received:Message-ID:Subject:From:To:Cc: Date:In-Reply-To:References:Autocrypt:Content-Type: Content-Transfer-Encoding:User-Agent:MIME-Version; bh=oLq4wxz5oEh5R1sh+VJJCccBAQfxGPFlpx22HnajP3g=; b=p/EKTGqCBJhLoYsvIOmGKNJmTk4eOOcbHYzG7dk6bZxLyGMPjzf/B1KLpEXWxyZ1HFaN JZIp+TeZlovtGMJIO7Fv95sBhHPdeR2fs15mDf77ylTpcJ+2rQX35m2luk/YMenRMHYgc HQ/DpBJZORXwuDLnV98BLt6+VnhVDnvn2yKREFBFzsb4O5+LswYvhPB4c+41qbmKEq755 y/tbA21L/2H9vi+7AmKvtN2GloVMGmOpMU5IIV7GBjEkZ7UWOnnAnjAax9XjNwWIIuE2c Cv59kCJnymg3cHfD/AobtmVHCcFuUKGVVkA+usQbjcHqPa0C8VLlidjBAtU+3URlkxQ== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=surriel.com; spf=pass smtp.mailfrom=surriel.com; dkim=pass header.d=surriel.com header.i=@surriel.com header.a=rsa-sha256 header.s=mail header.b=I4TZvnuF; arc=none smtp.remote-ip=96.67.55.147 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (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 40057606A31A; Tue, 27 Oct 2026 02:08:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 40057606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=surriel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=surriel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=surriel.com header.i=@surriel.com header.a=rsa-sha256 header.s=mail header.b=I4TZvnuF DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID; bh=oLq4wxz5oEh5R1sh+VJJCccBAQfxGPFlpx22HnajP3g=; b=I4TZvn uFx5nXaNn5b4N6dTFJOZnQFvfCyMSRe1WmZf0oJ6ac5FdYlGx4P4oZcraSi6f8oHxdUKQRL2hhMv2 k1T8Qhk4DMEliLIEGV8Z9vwg9OjZR0LHm1fw7Q4EGvmnlyqmSPcCxJDJVd3+v/SvoT1lDE5OhhWJh bB0TywZtbrrrqxcpI/RWp69SqjcAEJ93TnMT1V6Mt8msESZgTNg0CoUeCX2noFZdIztNs0cPT7B/y 9e9Au7mlP2j0PqR5y1+9tf4+O0p9v7VEND/Q6vD2t3xAaX7LNz89F3FQppIO6jBl/Ye+nt7mv8PxY jNU/oTDZc+eq68lcC1MXDWmrSHAA==; Received: from [2601:18c:8100:a0e0:2541:b86e:2586:d219] by shelob.surriel.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.99.5) (envelope-from ) id 1xLWaN-0000000B10v-3TRT; Tue, 27 Oct 2026 02:06:47 +0000 Message-ID: <639cb6dca4ab423272e05b90562ec49c7bdb12f9.camel@surriel.com> Subject: Re: [PATCH 04/46] mm/memfd: make f_pos accesses atomic From: Rik van Riel To: "David Hildenbrand (Arm)" , 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 , 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: 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, Josef Bacik , stable@vger.kernel.org Date: Mon, 26 Oct 2026 22:06:47 -0400 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> Autocrypt: addr=riel@surriel.com; prefer-encrypt=mutual; keydata=mQENBFIt3aUBCADCK0LicyCYyMa0E1lodCDUBf6G+6C5UXKG1jEYwQu49cc/gUBTTk33A eo2hjn4JinVaPF3zfZprnKMEGGv4dHvEOCPWiNhlz5RtqH3SKJllq2dpeMS9RqbMvDA36rlJIIo47 Z/nl6IA8MDhSqyqdnTY8z7LnQHqq16jAqwo7Ll9qALXz4yG1ZdSCmo80VPetBZZPw7WMjo+1hByv/ lvdFnLfiQ52tayuuC1r9x2qZ/SYWd2M4p/f5CLmvG9UcnkbYFsKWz8bwOBWKg1PQcaYHLx06sHGdY dIDaeVvkIfMFwAprSo5EFU+aes2VB2ZjugOTbkkW2aPSWTRsBhPHhV6dABEBAAG0HlJpayB2YW4gU mllbCA8cmllbEByZWRoYXQuY29tPokBHwQwAQIACQUCW5LcVgIdIAAKCRDOed6ShMTeg05SB/986o gEgdq4byrtaBQKFg5LWfd8e+h+QzLOg/T8mSS3dJzFXe5JBOfvYg7Bj47xXi9I5sM+I9Lu9+1XVb/ r2rGJrU1DwA09TnmyFtK76bgMF0sBEh1ECILYNQTEIemzNFwOWLZZlEhZFRJsZyX+mtEp/WQIygHV WjwuP69VJw+fPQvLOGn4j8W9QXuvhha7u1QJ7mYx4dLGHrZlHdwDsqpvWsW+3rsIqs1BBe5/Itz9o 6y9gLNtQzwmSDioV8KhF85VmYInslhv5tUtMEppfdTLyX4SUKh8ftNIVmH9mXyRCZclSoa6IMd635 Jq1Pj2/Lp64tOzSvN5Y9zaiCc5FucXtB9SaWsgdmFuIFJpZWwgPHJpZWxAc3VycmllbC5jb20+iQE +BBMBAgAoBQJSLd2lAhsjBQkSzAMABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRDOed6ShMTe g4PpB/0ZivKYFt0LaB22ssWUrBoeNWCP1NY/lkq2QbPhR3agLB7ZXI97PF2z/5QD9Fuy/FD/jddPx KRTvFCtHcEzTOcFjBmf52uqgt3U40H9GM++0IM0yHusd9EzlaWsbp09vsAV2DwdqS69x9RPbvE/Ne fO5subhocH76okcF/aQiQ+oj2j6LJZGBJBVigOHg+4zyzdDgKM+jp0bvDI51KQ4XfxV593OhvkS3z 3FPx0CE7l62WhWrieHyBblqvkTYgJ6dq4bsYpqxxGJOkQ47WpEUx6onH+rImWmPJbSYGhwBzTo0Mm G1Nb1qGPG+mTrSmJjDRxrwf1zjmYqQreWVSFEt26tBpSaWsgdmFuIFJpZWwgPHJpZWxAZmIuY29tP okBPgQTAQIAKAUCW5LbiAIbIwUJEswDAAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQznneko TE3oOUEQgAsrGxjTC1bGtZyuvyQPcXclap11Ogib6rQywGYu6/Mnkbd6hbyY3wpdyQii/cas2S44N cQj8HkGv91JLVE24/Wt0gITPCH3rLVJJDGQxprHTVDs1t1RAbsbp0XTksZPCNWDGYIBo2aHDwErhI omYQ0Xluo1WBtH/UmHgirHvclsou1Ks9jyTxiPyUKRfae7GNOFiX99+ZlB27P3t8CjtSO831Ij0Ip QrfooZ21YVlUKw0Wy6Ll8EyefyrEYSh8KTm8dQj4O7xxvdg865TLeLpho5PwDRF+/mR3qi8CdGbkE c4pYZQO8UDXUN4S+pe0aTeTqlYw8rRHWF9TnvtpcNzZw== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-2.fc44) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 On Tue, 2026-10-27 at 00:17 +0100, David Hildenbrand (Arm) wrote: > From: Josef Bacik >=20 >=20 > Set the flag when the memfd is created.=C2=A0 As for any other regular > file the > lock is only taken if the file is reachable in more than one way, and > nothing a memfd does in read or write waits for another operation on > the > same file.=C2=A0 This cannot be done for all alloc_file_pseudo() files: > anon > inode files such as eventfd are S_IFREG as well, and a blocked read > holding > ->f_pos_lock would lock out the write that is supposed to wake it. >=20 > Fix generated by an LLM and sent by Josef Bacik in private. >=20 > 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) Reviewed-by: Rik van Riel --=20 All Rights Reversed.