Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760061Ab2EIPws (ORCPT ); Wed, 9 May 2012 11:52:48 -0400 Received: from mail127.messagelabs.com ([216.82.250.115]:63162 "EHLO mail127.messagelabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758184Ab2EIPwq convert rfc822-to-8bit (ORCPT ); Wed, 9 May 2012 11:52:46 -0400 X-Env-Sender: hartleys@visionengravers.com X-Msg-Ref: server-12.tower-127.messagelabs.com!1336578765!5014676!1 X-Originating-IP: [216.166.12.32] X-StarScan-Version: 6.5.7; banners=-,-,- X-VirusChecked: Checked From: H Hartley Sweeten To: "gregkh@linuxfoundation.org" , Ian Abbott CC: "devel@driverdev.osuosl.org" , "fmhess@users.sourceforge.net" , Ian Abbott , Linux Kernel Date: Wed, 9 May 2012 10:52:34 -0500 Subject: RE: [PATCH] staging: comedi: remove __user annotation inside of struct's Thread-Topic: [PATCH] staging: comedi: remove __user annotation inside of struct's Thread-Index: Ac0t73pPX9hUq5RPTEiyW1D1TnDbHgAC3AgA Message-ID: References: <201205081641.00358.hartleys@visionengravers.com> <4FAA44D7.1040209@mev.co.uk> <20120509142436.GC11695@kroah.com> In-Reply-To: <20120509142436.GC11695@kroah.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2370 Lines: 60 On Wednesday, May 09, 2012 7:25 AM, gregkh@linuxfoundation.org wrote: > On Wed, May 09, 2012 at 11:20:07AM +0100, Ian Abbott wrote: >> On 2012-05-09 00:55, H Hartley Sweeten wrote: >>> On Tuesday, May 08, 2012 4:41 PM, H Hartley Sweeten wrote: >>>> >>>> The structs' comedi_insn, coomedi_insnlist, comedi_cmd, >>>> comedi_chaninfo, and comedi_rangeinfo are all passed to >>>> the kernel from user space using ioctl commands. They >>>> are then copied to kernel space using copy_from_user() >>>> before the data is passed to the drivers. >>>> >>>> The __user annotation should not be used with variables >>>> inside the struct. This produces a lot of sparse warnings >>>> like: >>>> >>>>warning: dereference of noderef expression >>>> >>>> Signed-off-by: H Hartley Sweeten >>>> Cc: Ian Abbott >>>> Cc: Mori Hess >>>> Cc: Greg Kroah-Hartman >>>> >>>> --- >>>> >>>> Note: This patch exposes some new warnings about different >>>> address space. These will be addressed. >>> >>> Please ignore this patch. >>> >>> It appears the annotations in the struct definitions are correct. >> >> Personally, I think you were on the mark with the patch. It's >> better to avoid using __user in comedi.h so it can be used as-is in >> user-space. All of the structures in comedi.h are used in user-space >> (although Comedilib uses its own version of comedi.h without all the >> typedef eliminations that have been done in "staging") and some of >> them are also deep-copied into kernel-space objects of the same >> type, where the pointers in the structs would no longer be >> user-space pointers. > > When the kernel exports .h files, stuff like this should work > "automatically", so there is no need to not put __user markings. > > So please, yes, continue to work to get this correct, it is very > essencial to ensure we don't mess stuff up. Greg, Based on the discussion I assume this patch is ok then. Do you want me to repost it? I'll work on fixing the other issues with the user <-> kernel transitions. Regards, Hartley -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/