Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932317Ab2EIP5G (ORCPT ); Wed, 9 May 2012 11:57:06 -0400 Received: from mail-pz0-f46.google.com ([209.85.210.46]:57192 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932297Ab2EIP45 (ORCPT ); Wed, 9 May 2012 11:56:57 -0400 Date: Wed, 9 May 2012 08:56:53 -0700 From: "gregkh@linuxfoundation.org" To: H Hartley Sweeten Cc: Ian Abbott , "devel@driverdev.osuosl.org" , "fmhess@users.sourceforge.net" , Ian Abbott , Linux Kernel Subject: Re: [PATCH] staging: comedi: remove __user annotation inside of struct's Message-ID: <20120509155653.GA23058@kroah.com> References: <201205081641.00358.hartleys@visionengravers.com> <4FAA44D7.1040209@mev.co.uk> <20120509142436.GC11695@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2689 Lines: 65 On Wed, May 09, 2012 at 10:52:34AM -0500, H Hartley Sweeten wrote: > 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? Sure, I'll review it with the other patches you have sent later today. > I'll work on fixing the other issues with the user <-> kernel transitions. Wonderful, thanks for the work you are doing on this code, it's greatly appreciated. greg k-h -- 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/