From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.128.46 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793212715; b=tcUKxLAIHBqE18qnWRKnP7t3eaITLF9Kem78lNPCU89cyF7uq2R+XSjtfvlsMK75kXoM zyqyfp52YnFrogJ/dYKtqJmdzAHZljHOmwAozXLSvbsfnNQKkT1tmPjf2KUB4ViXGRcUB A2Nxae1taTIHlUOV5VqNS5nQGtNxyJUQG/7TLdIpTHF+5esM7FgXdDzmrzUMnwWpmnl5e ck1Fx9sg8T/uPOxkRbYbLCwPuszCvjsbD44qNqVzO1VcSKN14q1rWT8EQq6ALlVHPdcgM 4lBNVEXxlDIj7oeBN2W7EcA9w42oSkFfZ5dYklabAgXhOfbZOczh71DsFCp5YoPi2Kg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793212715; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=VpA17SHHGuwrQBIEjd+s24NC7TfJ/mBAwe7vJ4GIKtI=; b=q9Rrwn51tvLY1lGMLbHgxgCQXmPjdi0g7R+Xd25Pz6BqhL+aonTl8i2gXlSpgdBms9Je 2tOyPqrluYhC6ra6A2eEMn17uOFxaf/ExMvCtdqZqy/NHd/wP6ISAg8eT1x9CLoVAimgg ykn0Wf/iNfpiGoZ8o183wOXAESdre2VqRbomLvCq4P6CB4MEejxDX6ix2OZ0K3oLv7Ct8 hoP4oYc/rsCDjP46SWWfD9DU33ncpbb4QlE8VlOA6iZmFSKglYosLLe0WZ5wYslhChDZf yNb6ZX3jgci/vlNw2cvR96ntykWpryG3MrUYd7TL7iHlhwGLmHtREtHxyOD5OYqq/lA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.remote-ip=209.85.128.46 Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6E588606A323 for ; Wed, 28 Oct 2026 18:38:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 6E588606A323 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-wm1-f46.google.com with SMTP id 5b1f17b1804b1-4a207b02a2cso9379325e9.1 for ; Wed, 28 Oct 2026 11:38:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1793212713; x=1793817513; darn=vger.kernel.org; h=content-transfer-encoding:content-type:mime-version:references :in-reply-to:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=VpA17SHHGuwrQBIEjd+s24NC7TfJ/mBAwe7vJ4GIKtI=; b=aQeeVIPMUiqwk6WocMaK2fvqFwOXq4+ME7x7LUdhEWRKNeI+L7qE3SAenqbAKKHIEu /dZzO+hCGRCttUuyJao2yyEMffqXY1XcIVpeVQuXvPFmqDkY/EY33VTXhu43HGxq74ZO +6o+Q/0xUxxMomTwd00jaif3ZMEwJPorfnEKewH/nJ0b6ROCYffVkQq5ewb6SwNj4ve/ LINfOhDwFhSEUcRKmkKUyBqhxHlvw/7HKboI/1J3227wiS+ln5iiwurOKfFN9Tl/kmUo s1Tx15RkKcq9clTXL2z/wjGiazmRXGXXnDvJaRXjBuvJ+RyHV7TfQw4joB+c0v7Pzi8L iDIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793212713; x=1793817513; h=content-transfer-encoding:content-type:mime-version:references :in-reply-to:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=VpA17SHHGuwrQBIEjd+s24NC7TfJ/mBAwe7vJ4GIKtI=; b=OGyhjSN6NNZ/bS8IDTU0bYhDnO5JKZCEL+dgrkVq0LXViwrNopFz8OQhavKYbsW4V0 u/83Ul+HM8KmXy5Do3Vxx8mbS+s5JM5el+JKNFB3mjpTtnroJrbJqiTzKEMaoOcMY2cF z1+0/9a51K5UzYyP+drTxT6bkD9hfhivoGldVfL+Fx7nAEBw24t87tWScwDROFr/uk4O PIAm7kJje8fT12Ia1dtzvQ4rxUOCHg5RJo+t5NjA8nZOEvx/pLfsDW6mt0DdFi+cOvTQ uKCpG6Nd9Cd08nT2dR6/GWOCyS+C8cEz0UGg3BNeRosxnQDw/SBiPQA0l2QlSAgLudqg 5uOA== X-Forwarded-Encrypted: i=1; AKwUvBxahxYxPAd3mW+E6SPshdRVdJDlfGM5uI6IoWNZYPATM4CAiOyg2+LY5OuRXuycRoC5DWUGWjk=@vger.kernel.org X-Gm-Message-State: AFq9FYLp7AWlN4joOVRFciLh9FU/vd+PygEhiPsT94qg9987TzO8YLNH OIlmkqod1SVuow22GwYNXMMiels23XpIVCd2P3uIyC9GlfPcfT50+RtX X-Gm-Gg: AYBFou3NP/PL1N3/XajHWF9AnD/nH9+fPjsNFJSOvm/q97TDnzasYiMrA76TKRza+rs CrBKevHNISOPWE3DcL/0JLYYgsseSPTLjL1rV57BBDJg22AaLJQsM+21wDUWBzZ1C1ZrQ4GtvqG iZ8ou9MZ6N3xmfkFgLF8rQnLJ9YIcTNqkq22yAdul/DzAAqd3loIjZUkx9NwEnifuxpsBqUuxr/ SXNPvOu6GDaU6qcJ94OvKzr0B4cAJ0GRzdZQn98JRLYVXEVbK3Mur3DeXrcCIrdn46HdPpntWY8 nLbwZTjGB6/1A5vdZn3dlZKZ/ADodjP3XJsdC6D3+Cwr5Gq4rsWd33rKvvd94gNDzddrYTu3lBx LxRvu5kOS+W45RYx4rMBp29xOdeDaRIC2rY/Ne6TVqaVvwHhXCQdcPBWoYDPZkAXrB+q3sn8zD5 R6yZf0q/BxY5Q604oIRxFG+Gmf2ZcLrm+HdRj4cyJsZxWneAqUDcoG7kDEX5o1GxuSnqlkJe//j 0GpDCYm9dTj18S7bNj4SuGUVYWBv6XeTf0Yp4AuD4mTVI8LQK3tyk0FsLXL7ebf+FScv3KI8j9q aW1YbUluoS9OwUbJk8b7Fa0n23HMg86jNW2db5/Ajtp8vrcE1p/YhKVixgjqyhE1QA== X-Received: by 2002:a05:600c:3541:b0:4a5:a5ca:de1d with SMTP id 5b1f17b1804b1-4a9675dc907mr75026265e9.30.1793212712626; Wed, 28 Oct 2026 11:38:32 -0700 (PDT) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4aa80f04723sm10842695e9.5.2026.10.28.11.38.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 28 Oct 2026 11:38:32 -0700 (PDT) Date: Wed, 28 Oct 2026 18:38:30 +0000 From: David Laight To: Christoph Hellwig Cc: Reid Downing , Carlos Maiolino , linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, "Darrick J . Wong" , Eric Sandeen , Christoph Hellwig , stable@vger.kernel.org Subject: Re: [PATCH v2] xfs: fix wrong compat fields in xfs_ioctl32_bstat_copyin() Message-ID: <20261028183831.055627aa@pumpkin> In-Reply-To: References: <20261027161748.2760321-1-skibletz@gmail.com> <20261027164911.578ef6e7@pumpkin> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 28 Oct 2026 08:18:40 -0700 Christoph Hellwig wrote: > On Tue, Oct 27, 2026 at 04:49:11PM +0000, David Laight wrote: > > On Tue, 27 Oct 2026 12:17:48 -0400 > > Reid Downing wrote: > > > > > bs_blocks and bs_xflags were both read from bstat32->bs_size. > > > Read each one from its own field instead. > > > > It would be much better to do a single copy_from_user() of the entire > > compat structure and copy the fields to the standard one. > > Care to explain why it would be "much better" to do two copies instead of > one? The only benefits from copy_from/to_user over the current > get_put/user is avoidind the conctant user access disabling/enabling, That is a massive hit. The current code also has all the conditionals from access_ok(). > but the scoped uaccess thing would do the same. True, but unnecessarily 'technical' for this bit of code. You also save all the exception table entries - so the code size would be rather smaller. David