Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267767AbUIGJfs (ORCPT ); Tue, 7 Sep 2004 05:35:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267772AbUIGJfs (ORCPT ); Tue, 7 Sep 2004 05:35:48 -0400 Received: from ns.virtualhost.dk ([195.184.98.160]:31466 "EHLO virtualhost.dk") by vger.kernel.org with ESMTP id S267767AbUIGJfp (ORCPT ); Tue, 7 Sep 2004 05:35:45 -0400 Date: Tue, 7 Sep 2004 11:34:37 +0200 From: Jens Axboe To: Paul Mackerras Cc: Jesper Juhl , LKML Subject: Re: [PATCH] remember to check return value from __copy_to_user() in cdrom_read_cdda_old() Message-ID: <20040907093437.GK6323@suse.de> References: <20040907080223.GF6323@suse.de> <16701.32784.10441.884090@cargo.ozlabs.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <16701.32784.10441.884090@cargo.ozlabs.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 980 Lines: 26 On Tue, Sep 07 2004, Paul Mackerras wrote: > Jens Axboe writes: > > > __copy_to_user is the unchecking version of copy_to_user. > > It doesn't range-check the address, but it does return non-zero > (number of bytes not copied) if it encounters a fault writing to the > user buffer. but it doesn't matter, if it returns non-zero then something happened between the access_ok() and the actual copy because the user app did something silly. so I don't care much really, I think the major point is the kernel will cope. you could remove the access_ok() and change it to a copy_to_user() instead, I don't care either way. it's the old and slow interface which really never is used unless things have gone wrong anyways. -- Jens Axboe - 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/