From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751616AbaKYBRJ (ORCPT ); Mon, 24 Nov 2014 20:17:09 -0500 Received: from mail.kernel.org ([198.145.19.201]:51265 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751402AbaKYBRH (ORCPT ); Mon, 24 Nov 2014 20:17:07 -0500 Date: Mon, 24 Nov 2014 22:17:01 -0300 From: Arnaldo Carvalho de Melo To: Andi Kleen Cc: Namhyung Kim , Peter Zijlstra , Ingo Molnar , Paul Mackerras , Namhyung Kim , LKML , Jiri Olsa , David Ahern , Frederic Weisbecker , Brendan Gregg Subject: Re: perf/branch-history branch build broken with NO_DEMANGLE=1 perf hists browser: Print overhead percent value for first-level callchain Message-ID: <20141125011701.GG13167@kernel.org> References: <20141124145227.GE18625@kernel.org> <20141124152312.GA13167@kernel.org> <20141124152541.GB13167@kernel.org> <20141124153204.GC13167@kernel.org> <20141124154841.GD13167@kernel.org> <20141124212308.GE13167@kernel.org> <20141124225244.GS12538@two.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141124225244.GS12538@two.firstfloor.org> X-Url: http://acmel.wordpress.com 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 Em Mon, Nov 24, 2014 at 11:52:44PM +0100, Andi Kleen escreveu: > > [root@zoo acme]# perf record -a -g -b sleep 2s > > [ perf record: Captured and wrote 3.033 MB perf.data (~132504 samples) ] > > [root@zoo acme]# perf report --stdio --branch-history > > # To display the perf.data header info, please use --header/--header-only options. > > BFD: Dwarf Error: Offset (2585882475) greater than or equal to .debug_str size (44321517). > > BFD: Dwarf Error: Could not find abbrev number 11800. > > > > BFD: Dwarf Error: Offset (83496016) greater than or equal to .debug_str size (44321517). > > BFD: Dwarf Error: Offset (48628447) greater than or equal to .debug_str size (44321517). > > (END)Segmentation fault (core dumped) > > [root@zoo acme]# > > Will investigate this later today/tomorrow, if nobody finds a fix in the meantime. > I cannot reproduce this. > For me it looks like you have some binary or debuginfo that your libbfd > doesn't like. --branch-history resolves all addresses as srcline, > so it will actually walk all the line numbers. > Can you please find out which one it is? Probably can be seen > by just going up a few levels in gdb and dumping the event. > If you can find the address that explodes you can also try it directly with > addr2line. If that works it's some problem in the perf implementation. Right, I'll try and figure this out, since you didn't manage to easily reproduce this. > It is likely that it would need to be fixed in libbfd. > > To work around it we could turn off force resolving the srcline, > but that would make the output much less useful too unfortuantely... I'll try to find out if there is something that can flag a file as "unsafe" to feed libbfd with, so that we can have a workaround for known buggy libbfds, if that ends up being really the case. - Arnaldo