From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 07 Feb 2003 01:21:24 +0000 (GMT) Received: from cm19173.red.mundo-r.com ([IPv6:::ffff:213.60.19.173]:8489 "EHLO trasno.mitica") by linux-mips.org with ESMTP id ; Fri, 7 Feb 2003 01:21:23 +0000 Received: by trasno.mitica (Postfix, from userid 1001) id C31C4C4B1; Fri, 7 Feb 2003 02:20:58 +0100 (CET) To: Jun Sun Cc: Vivien Chappelier , Ralf Baechle , linux-mips@linux-mips.org Subject: Re: [PATCH 2.5] clear USEDFPU in copy_thread X-Url: http://people.mandrakesoft.com/~quintela From: Juan Quintela In-Reply-To: <20030206164342.G13258@mvista.com> (Jun Sun's message of "Thu, 6 Feb 2003 16:43:42 -0800") User-Agent: Gnus/5.090012 (Oort Gnus v0.12) Emacs/21.2.92 (i386-mandrake-linux-gnu) References: <20030206164342.G13258@mvista.com> Date: Fri, 07 Feb 2003 02:20:58 +0100 Message-ID: <86hebgj37p.fsf@trasno.mitica> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 1360 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: quintela@mandrakesoft.com Precedence: bulk X-list: linux-mips >>>>> "jun" == Jun Sun writes: Hi jun> Even if you don't have it cleared in start_thread(), things jun> should be generally OK. You will have some dirty FPU content jun> instead of a all-zero one when you start a new program. But then jun> since all sane program should assign register values before they jun> first time use them, so this bug should be well hidden. I don't remind the exact details, but the problem appears to be the security implications, you can see last values of previous process. Yes, I still have to find a way where that is useful, but ... Later, Juan. -- In theory, practice and theory are the same, but in practice they are different -- Larry McVoy