From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751477AbdJDHSt (ORCPT ); Wed, 4 Oct 2017 03:18:49 -0400 Received: from mga11.intel.com ([192.55.52.93]:19762 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751331AbdJDHSr (ORCPT ); Wed, 4 Oct 2017 03:18:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.42,476,1500966000"; d="scan'208";a="906525426" Subject: Re: perf script : wrong symoff in callchain To: Matthieu CASTET Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Chris Phlipot References: <20171003121922.7d818faa@perruche.parrot.biz> <42f1fb90-246c-782f-a8d7-2d126968f4b0@intel.com> <20171003134454.037783e6@perruche.parrot.biz> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki Message-ID: <07b62c14-eb07-9178-0a91-9661672b3a5f@intel.com> Date: Wed, 4 Oct 2017 10:12:00 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <20171003134454.037783e6@perruche.parrot.biz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/10/17 14:45, Matthieu CASTET wrote: > Le Tue, 3 Oct 2017 13:34:37 +0300, > Adrian Hunter a écrit : > >> On 03/10/17 13:19, Matthieu CASTET wrote: >>> Hi, >>> >>> while using perf on x86_64, I saw strange output for symoff. >>> >>> $ perf record -g -- sleep 1 >>> $ perf script -F comm,tid,pid,time,ip,sym,dso,symoff >>> >>> [...] >>> sleep 11656/11656 1045318.546436: >>> 7fff9542e5b5 __d_lookup_rcu+0x80006ae02035 ([kernel.kallsyms]) >>> 7fff9541e132 lookup_fast+0x80006ae02052 ([kernel.kallsyms]) >>> 7fff9541eae8 walk_component+0x80006ae02048 ([kernel.kallsyms]) >>> 7fff9541efa2 link_path_walk+0x80006ae021b2 ([kernel.kallsyms]) >>> 7fff9541c92d path_init+0x80006ae021bd ([kernel.kallsyms]) >>> 7fff9542100b path_openat+0x80006ae020fb ([kernel.kallsyms]) >>> 7fff953c14fe handle_mm_fault+0x80006ae020ee ([kernel.kallsyms]) >>> 7fff95423669 do_filp_open+0x80006ae02099 ([kernel.kallsyms]) >>> 7fff95433414 __alloc_fd+0x80006ae02044 ([kernel.kallsyms]) >>> 7fff9540ff6e do_sys_open+0x80006ae0212e ([kernel.kallsyms]) >>> 7fff9540ff6e do_sys_open+0x80006ae0212e ([kernel.kallsyms]) >>> 7fff95850abb system_call_fast_compare_end+0x80006ae0200c ([kernel.kallsyms]) >>> 2aecf _nl_load_locale_from_archive+0xffff014b5a92841f (/lib/x86_64-linux-gnu/libc-2.24.so) >>> >>> >>> I tried to revert a4eb24a49566db77ee999b46603f602a0302f481 and I got >>> good result : >>> [...] >>> sleep 11656/11656 1045318.546436: >>> 7fff9542e5b5 __d_lookup_rcu+0x35 ([kernel.kallsyms]) >>> 7fff9541e132 lookup_fast+0x52 ([kernel.kallsyms]) >>> 7fff9541eae8 walk_component+0x48 ([kernel.kallsyms]) >>> 7fff9541efa2 link_path_walk+0x1b2 ([kernel.kallsyms]) >>> 7fff9541c92d path_init+0x1bd ([kernel.kallsyms]) >>> 7fff9542100b path_openat+0xfb ([kernel.kallsyms]) >>> 7fff953c14fe handle_mm_fault+0xee ([kernel.kallsyms]) >>> 7fff95423669 do_filp_open+0x99 ([kernel.kallsyms]) >>> 7fff95433414 __alloc_fd+0x44 ([kernel.kallsyms]) >>> 7fff9540ff6e do_sys_open+0x12e ([kernel.kallsyms]) >>> 7fff9540ff6e do_sys_open+0x12e ([kernel.kallsyms]) >>> 7fff95850abb system_call_fast_compare_end+0xc ([kernel.kallsyms]) >>> 2aecf _nl_load_locale_from_archive+0x41f (/lib/x86_64-linux-gnu/libc-2.24.so) >>> >>> >>> Any idea ? >> >> It could be the problem with add_callchain_ip() described here: >> >> https://www.spinics.net/lists/linux-perf-users/msg03172.html > > The db-export code removed the remapping [1] > > So there a mix of mapping in callchain code : > - add_callchain_ip() store al.addr (ip remapped) > - fill_callchain_info do the translation (map_ip) > - sample__fprintf_callchain do the translation > - call_path_from_sample (db-export) don't do anymore the translation > > > So what should we do : > - assume we store al.addr and remove mapping from all consumers ? Seems it got changed to al.addr (per below), so I guess we should remove mapping from all consumers. commit 5550171b2a9f8df26ff483051d060db06376b26d Author: Andi Kleen Date: Wed Nov 12 18:05:21 2014 -0800 perf callchain: Use al.addr to set up call chain Use the relative address, this makes get_srcline work correctly in the end. Signed-off-by: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lkml.kernel.org/r/1415844328-4884-4-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 84390ee..d97309c 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -1406,7 +1406,7 @@ static int add_callchain_ip(struct thread *thread, } } - return callchain_cursor_append(&callchain_cursor, ip, al.map, al.sym); + return callchain_cursor_append(&callchain_cursor, al.addr, al.map, al.sym); } struct branch_info *sample__resolve_bstack(struct perf_sample *sample, > - store ip and do the mapping in consumers ? > > > > [1] > commit 7a2544c004a6c576b1e307f30925b165affe6a22 > Author: Chris Phlipot > Date: Tue May 10 20:26:48 2016 -0700 > > perf script: Fix callchain addresses in db-export > > Remove the call to map_ip() to adjust al.addr, because it has already > been called when assembling the callchain, in: > > thread__resolve_callchain_sample(perf_sample) > add_callchain_ip(ip = perf_sample->callchain->ips[j]) > thread__find_addr_location(addr = ip) > thread__find_addr_map(addr) { > al->addr = addr > if (al->map) > al->addr = al->map->map_ip(al->map, al->addr); > } > > Calling it a second time can result in incorrect addresses being used. > This can have effects such as duplicate symbols being created and > exported. >