From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753260AbZEIRol (ORCPT ); Sat, 9 May 2009 13:44:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752191AbZEIRoc (ORCPT ); Sat, 9 May 2009 13:44:32 -0400 Received: from taverner.CS.Berkeley.EDU ([128.32.168.222]:57456 "EHLO taverner.cs.berkeley.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751667AbZEIRob (ORCPT ); Sat, 9 May 2009 13:44:31 -0400 To: linux-kernel@vger.kernel.org Path: not-for-mail From: daw@cs.berkeley.edu (David Wagner) Newsgroups: isaac.lists.linux-kernel Subject: Re: [RFC] convert ftrace syscall tracer to TRACE_EVENT() Date: Sat, 9 May 2009 17:44:32 +0000 (UTC) Organization: University of California, Berkeley Message-ID: References: <20090508210347.GA3121@redhat.com> <20090509133306.GA20684@elte.hu> <20090509135046.GA2344@Krystal> Reply-To: daw-news@cs.berkeley.edu (David Wagner) NNTP-Posting-Host: taverner.cs.berkeley.edu X-Trace: taverner.cs.berkeley.edu 1241891072 20039 128.32.168.222 (9 May 2009 17:44:32 GMT) X-Complaints-To: news@taverner.cs.berkeley.edu NNTP-Posting-Date: Sat, 9 May 2009 17:44:32 +0000 (UTC) X-Newsreader: trn 4.0-test76 (Apr 2, 2001) Originator: daw@taverner.cs.berkeley.edu (David Wagner) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Mathieu Desnoyers wrote: > I would expect to use copy_string_from_user (for strings) > and copy_from_user for structures, because without any strings > (especially), the trace information become much less useful. Why isn't this racey? (Copying from user space twice can give you two different results.)