From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756596AbZBIOUw (ORCPT ); Mon, 9 Feb 2009 09:20:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754500AbZBIOUn (ORCPT ); Mon, 9 Feb 2009 09:20:43 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:34093 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753994AbZBIOUm (ORCPT ); Mon, 9 Feb 2009 09:20:42 -0500 Date: Mon, 9 Feb 2009 15:20:30 +0100 From: Ingo Molnar To: Steven Rostedt Cc: Lai Jiangshan , Linux Kernel Mailing List Subject: Re: [PATCH 1/2] ring_buffer: fix typing mistake Message-ID: <20090209142030.GA28580@elte.hu> References: <498FCB5A.5030207@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Steven Rostedt wrote: > > On Mon, 9 Feb 2009, Lai Jiangshan wrote: > > > > > Impact: Fix bug > > > > I found several very very curious line. > > It's so curious that it may be brought by typing mistake. > > > > When (cpu_buffer->reader_page == cpu_buffer->commit_page): > > > > 1) We haven't copied it for bpage is changed: > > bpage = cpu_buffer->reader_page->page; > > memcpy(bpage->data, cpu_buffer->reader_page->page->data + read ... ) > > 2) We need update cpu_buffer->reader_page->read, but > > "cpu_buffer->reader_page += read;" is not right. > > Ouch! That is a bug. > > Ingo, this is an urgent fix. Want me to pull it in and send it off to you? Please do, yes. Ingo