Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752076Ab0FHHww (ORCPT ); Tue, 8 Jun 2010 03:52:52 -0400 Received: from earthlight.etchedpixels.co.uk ([81.2.110.250]:54041 "EHLO www.etchedpixels.co.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751628Ab0FHHwv (ORCPT ); Tue, 8 Jun 2010 03:52:51 -0400 Date: Tue, 8 Jun 2010 09:01:20 +0100 From: Alan Cox To: "Masayuki Ohtake" Cc: "LKML" , "Andrew" , "Intel OTC" , "Wang, Qi" , "Wang, Yong Y" Subject: Re: [PATCH] Topcliff PHUB: Generate PacketHub driver Message-ID: <20100608090120.75bf7c80@lxorguk.ukuu.org.uk> In-Reply-To: <000601cb06cd$f48d3bb0$66f8800a@maildom.okisemi.com> References: <4C0DCE87.1090802@dsn.okisemi.com> <000601cb06cd$f48d3bb0$66f8800a@maildom.okisemi.com> X-Mailer: Claws Mail 3.7.6 (GTK+ 2.18.9; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 902 Lines: 27 On Tue, 8 Jun 2010 14:46:31 +0900 "Masayuki Ohtake" wrote: > Hi Alan > > > > Remember here ioctl isn't single threaded so you may want to double check > > > > > some of these > > > > The above copy_from_user is Copy global variable to local variable. > > Thus, We think this code has re-entrant. > The above is not true. > Our ioctl routine is just used under single pthread. What if someone else chooses to open it and run multiple threads through it. What if the code changes. What about malicious attempts to confuse the driver ? The fact your own current userspace does not do this does not mean it can be ignored. Alan -- 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/