From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760612Ab2EKPBS (ORCPT ); Fri, 11 May 2012 11:01:18 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:36960 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758262Ab2EKPBR (ORCPT ); Fri, 11 May 2012 11:01:17 -0400 Date: Fri, 11 May 2012 12:01:11 -0300 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Peter Zijlstra , Paul Mackerras , Ingo Molnar , LKML , Frederic Weisbecker Subject: Re: [PATCH] perf top: Fix a race in callchain handling Message-ID: <20120511150111.GA2485@infradead.org> References: <1336231388-12347-1-git-send-email-namhyung@gmail.com> <1336242167.2463.138.camel@laptop> <20120505235319.GB2150@infradead.org> <1336271107.1534.12.camel@leonhard> <20120506183212.GB2485@infradead.org> <878vh4srmh.fsf@sejong.aot.lge.com> <87vck3ii18.fsf@sejong.aot.lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87vck3ii18.fsf@sejong.aot.lge.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Fri, May 11, 2012 at 11:10:59AM +0900, Namhyung Kim escreveu: > On Mon, 07 May 2012 10:32:22 +0900, Namhyung Kim wrote: > > I thought about it before, but it still cannot protect it from accessing > > a hists by multiple concurrent threads. IOW if two threads call the > > function to a same hists at the same time, ->callchain_collapse_cursor > > would still get the race problem - so crashed. > > > > I guess callchain_cursor should be thread-local, eventually. No need to > > make it hist-local IMHO. > > So, any thoughts? Can you try writing a patch using TLS? - Arnaldo