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 9D7AB606A326 for ; Wed, 4 Nov 2026 01:03:36 +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=e3TItm7X; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FGmiCuxI 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=Ds/UOfmOvJuR4wrZT7xOsfABBaxA7lDS0xMWduVSe/g=; b=e3TItm7XrfvVNJs1Q9DbSF6w2L StkTqoUCtRustINnMaW8UXF5I3aowB7b+MnDk6TKncC9yetNqqDnQXkooCQ2+Eu2/1jc2n7NfwjyR R4cViRFHpqZXeI2upCeZUh8Qe+pevl6WdihRfP9fG04mstaP9Bc1vDqfugxjiATqwx0yjJJPA5fft wFkXhWAKRe1XXJAXDeOCKKgjViDoDJPVUr/bNr77QhlW+LbxeISDOVdYO1afW71cevssZ6Ch/OkEj HsPKOoj7WadspBMM9IUZCD6FMsiiPL1QOws2Eg5NFUU25InBKaWGV9Ok7dpcfbEmEdTariAybqTAe GWlLDs/g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOPPc-000000042U6-1794; Wed, 04 Nov 2026 01:03:36 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOPPa-000000042Ra-3Koh for kexec@lists.infradead.org; Wed, 04 Nov 2026 01:03:34 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 82ACC40598; Wed, 4 Nov 2026 01:03:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8E2741F000C1; Wed, 4 Nov 2026 01:03:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793754214; bh=Ds/UOfmOvJuR4wrZT7xOsfABBaxA7lDS0xMWduVSe/g=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=FGmiCuxIMEo4PfiK5wDWDqKO9ioOYOT10Q+/s4I9HzzzSEmfpY28pZ2yQ53yvRkCR 3eb+eTya1lHrl4zGKw3GKiK083UPvSW2fhMOYO0ATc2UAxg1ml7Xx8esy71OLR0Ejr 4Pds7FdyP/wefIADkTjysL6iMxqgywYhIbsKiPb7wKrqzRfbqzUD6qgzL3KPyc+gqT RZRAyQDLQRb7bHd8kc7aavZKPSypVLnnn1ztT1kglRYz9Z8RwjqKxuAmQo9WjKTxpd tBL6pVIPJGU9x1klIzD0DW/IrY41u3y2Yj7KRohhBUKtTTfNQ4OpKO2UyNI6thhKYU E06vj7HHGWBQw== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 09/10] mm/shmem_luo: Allow retrieving tmpfs files with O_RDONLY To: "David Matlack" , kexec@lists.infradead.org Cc: "Alexander Graf" , "Andrew Morton" , "Baolin Wang" , "Christian Brauner" , "David Hildenbrand" , "Hugh Dickins" , "Jonathan Corbet" , "Liam R. Howlett" , "Lorenzo Stoakes" , "Michal Hocko" , "Mike Rapoport" , "Pasha Tatashin" , "Pratyush Yadav" , "Randy Dunlap" , "Samiullah Khawaja" , "Shuah Khan" , "Suren Baghdasaryan" , "Vlastimil Babka" In-Reply-To: <20261103010216.3447716-10-dmatlack@google.com> References: <20261103010216.3447716-1-dmatlack@google.com> <20261103010216.3447716-10-dmatlack@google.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 04 Nov 2026 01:03:33 +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=-10.9 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: > Allow userspace to pass O_RDONLY in struct liveupdate_shmem_retrieve_arg > to retrieve a tmpfs file read-only. >=20 > open() requires write access for O_TMPFILE, so create the file writable > like before, then reopen it read-only with dentry_open() using the flags > of the writable file, which file_open_root() normalized, and drop the > writable file. Like open(), which grants the requested access to a new > file regardless of its mode, don't check permission for the read-only > open. >=20 > Retrieving a file read-only allows a restored binary to be executed > before the session is finished. LUO keeps the retrieved file open until > then, and executing a binary that is open for writing fails with > -ETXTBSY. Being able to execute restored binaries right away matters > when they are needed to finish restoring the system, e.g. to bring up > the services that retrieve and finish the remaining sessions. >=20 > Signed-off-by: David Matlack Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261103010216.3447= 716-1-dmatlack@google.com?part=3D9