From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754221AbaI2PVr (ORCPT ); Mon, 29 Sep 2014 11:21:47 -0400 Received: from mga09.intel.com ([134.134.136.24]:3835 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751420AbaI2PVq (ORCPT ); Mon, 29 Sep 2014 11:21:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,620,1406617200"; d="scan'208";a="610322669" Date: Mon, 29 Sep 2014 08:21:45 -0700 From: Andi Kleen To: Peter Zijlstra Cc: Andi Kleen , dave@sr71.net, linux-kernel@vger.kernel.org, mingo@kernel.org, eranian@google.com, x86@kernel.org Subject: Re: [PATCH 1/2] Use faster check for modules in backtrace on 64bit Message-ID: <20140929152145.GB1629@tassilo.jf.intel.com> References: <1411774277-4198-1-git-send-email-andi@firstfloor.org> <1411774277-4198-2-git-send-email-andi@firstfloor.org> <20140929114212.GG5430@worktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140929114212.GG5430@worktop> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 29, 2014 at 01:42:12PM +0200, Peter Zijlstra wrote: > On Fri, Sep 26, 2014 at 04:31:16PM -0700, Andi Kleen wrote: > > > > This has the (small) potential to get a false positive on a pointer to a > > data segment in a module. However since we also use the frame pointer > > chain as initial sanity check I think the danger of this is very low. > > > > So this has come up several times; and the answer has always been, why > not make the __module_address() thing a rb-tree instead of a linear > loop. So I suppose I'll ask that again, why not? Why do things complicated, if they can be done simple too? -Andi -- ak@linux.intel.com -- Speaking for myself only