From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Li Subject: Re: [PATCH] Add const to pointer qualifiers for __chk_user_ptr and __chk_io_ptr. Date: Mon, 26 Mar 2007 11:01:55 -0700 Message-ID: <20070326180155.GA24764@chrisli.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from alnrmhc15.comcast.net ([204.127.225.95]:50708 "EHLO alnrmhc15.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753675AbXCZSlW (ORCPT ); Mon, 26 Mar 2007 14:41:22 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Russ Cox Cc: linux-kernel@vger.kernel.org, linux-sparse@vger.kernel.org On Mon, Mar 26, 2007 at 11:23:56AM -0400, Russ Cox wrote: > Change prototypes for __chk_user_ptr and __chk_io_ptr > to take const void* instead of void*, so that code can pass > const void* to them. (Right now sparse does not warn > about passing const void* to void* functions, but that > is a separate bug that I believe Josh is working on, > and once sparse does check this, the changed prototypes > will be necessary.) I don't think it is needed. The __user has noderef attribute. Which means it is not allow to dereference the pointer. The const qualifier allow read dereference, only write is not allowed. Adding const here will likely force the caller to do a cast at the pointer arguments. Which defeats the checker. Sparse allow passing const void* to void* is a different issue. Chris