From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-acpi-owner@kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
X-Spam-Level: 
X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,
	HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS
	autolearn=no autolearn_force=no version=3.4.0
Received: from mail.kernel.org (mail.kernel.org [198.145.29.99])
	by smtp.lore.kernel.org (Postfix) with ESMTP id 48082C433E6
	for <linux-acpi@archiver.kernel.org>; Sun, 14 Feb 2021 23:58:57 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by mail.kernel.org (Postfix) with ESMTP id 1730A64E52
	for <linux-acpi@archiver.kernel.org>; Sun, 14 Feb 2021 23:58:57 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S230003AbhBNX6l (ORCPT <rfc822;linux-acpi@archiver.kernel.org>);
        Sun, 14 Feb 2021 18:58:41 -0500
Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37434 "EHLO
        lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
        with ESMTP id S229981AbhBNX6k (ORCPT
        <rfc822;linux-acpi@vger.kernel.org>); Sun, 14 Feb 2021 18:58:40 -0500
Received: from zeniv-ca.linux.org.uk (zeniv-ca.linux.org.uk [IPv6:2607:5300:60:148a::1])
        by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B8E4BC061574;
        Sun, 14 Feb 2021 15:58:00 -0800 (PST)
Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94 #2 (Red Hat Linux))
        id 1lBRH4-00E3lo-QQ; Sun, 14 Feb 2021 23:57:58 +0000
Date:   Sun, 14 Feb 2021 23:57:58 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Ben Widawsky <ben.widawsky@intel.com>
Cc:     linux-cxl@vger.kernel.org, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org,
        linux-pci@vger.kernel.org, Bjorn Helgaas <helgaas@kernel.org>,
        Chris Browy <cbrowy@avery-design.com>,
        Christoph Hellwig <hch@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        David Hildenbrand <david@redhat.com>,
        David Rientjes <rientjes@google.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Jon Masters <jcm@jonmasters.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Vishal Verma <vishal.l.verma@intel.com>,
        "John Groves (jgroves)" <jgroves@micron.com>,
        "Kelley, Sean V" <sean.v.kelley@intel.com>,
        kernel test robot <lkp@intel.com>,
        Dan Williams <dan.j.willams@intel.com>
Subject: Re: [PATCH v2 4/8] cxl/mem: Add basic IOCTL interface
Message-ID: <YCm5Bs2NalmHgeZn@zeniv-ca.linux.org.uk>
References: <20210210000259.635748-1-ben.widawsky@intel.com>
 <20210210000259.635748-5-ben.widawsky@intel.com>
 <YClQEefYBR+YKBUv@zeniv-ca.linux.org.uk>
 <20210214231456.xnwitliczv6qwmjv@intel.com>
 <YCm3NFqO9gVtXOZP@zeniv-ca.linux.org.uk>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <YCm3NFqO9gVtXOZP@zeniv-ca.linux.org.uk>
Sender: Al Viro <viro@ftp.linux.org.uk>
Precedence: bulk
List-ID: <linux-acpi.vger.kernel.org>
X-Mailing-List: linux-acpi@vger.kernel.org

On Sun, Feb 14, 2021 at 11:50:12PM +0000, Al Viro wrote:
> 	check that len is reasonable
> 	p = kmalloc(offsetof(struct foo, string[len]), GFP_KERNEL);
> 	copy_from_user(p, user_object, len);
			offsetof(struct foo, string[len]), that is