Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751775AbdFEKrZ (ORCPT ); Mon, 5 Jun 2017 06:47:25 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43468 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751338AbdFEKrX (ORCPT ); Mon, 5 Jun 2017 06:47:23 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 239A7C0587CC Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=jolsa@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com 239A7C0587CC Date: Mon, 5 Jun 2017 12:47:20 +0200 From: Jiri Olsa To: Arnaldo Carvalho de Melo Cc: Milian Wolff , Linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Namhyung Kim , acme@kernel.org, Jan Kratochvil Subject: Re: [PATCH 2/2] perf report: report module before querying isactivation in dwfl unwind Message-ID: <20170605104720.GC28871@krava> References: <20170602143753.16907-1-milian.wolff@kdab.com> <20170602143753.16907-2-milian.wolff@kdab.com> <20170602152508.GC7901@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170602152508.GC7901@redhat.com> User-Agent: Mutt/1.8.0 (2017-02-23) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 05 Jun 2017 10:47:23 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6826 Lines: 132 On Fri, Jun 02, 2017 at 12:25:08PM -0300, Arnaldo Carvalho de Melo wrote: > Em Fri, Jun 02, 2017 at 04:37:53PM +0200, Milian Wolff escreveu: > > The PC returned by dwfl_frame_pc may map into a not-yet-reported > > module. We have to report it before we continue unwinding. But when > > we query for the isactivation flag in dwfl_frame_pc, libdw will > > actually do one more unwinding step internally which can then break > > and lead to missed frames or broken stacks. > > > > With libunwind we get e.g.: sounds like a libdw design issue.. Jan is there a specific way to handle the case that Milian described? thanks, jirka > > Thanks, > > - Arnaldo > > > ~~~~~ > > heaptrack_gui 2228 135073.400474: 613969 cycles: > > 108c8e [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 1093bc [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 109e7b QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) > > 1470ff [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 147f67 QSystemLocale::query (/usr/lib/libQt5Core.so.5.8.0) > > 109fbf QLocalePrivate::updateSystemPrivate (/usr/lib/libQt5Core.so.5.8.0) > > 10aa27 QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) > > 1e02c3 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 2113bb [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 211505 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 1b5df0 QFileInfo::exists (/usr/lib/libQt5Core.so.5.8.0) > > 92eb2 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 93423 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 93d2a QLibraryInfo::location (/usr/lib/libQt5Core.so.5.8.0) > > 2170af [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 297c53 QCoreApplicationPrivate::init (/usr/lib/libQt5Core.so.5.8.0) > > f7cde QGuiApplicationPrivate::init (/usr/lib/libQt5Gui.so.5.8.0) > > 1589e8 QApplicationPrivate::init (/usr/lib/libQt5Widgets.so.5.8.0) > > 78622 main (/home/milian/projects/compiled/other/bin/heaptrack_gui) > > 20439 __libc_start_main (/usr/lib/libc-2.25.so) > > 78299 _start (/home/milian/projects/compiled/other/bin/heaptrack_gui) > > > > heaptrack_gui 2228 135073.401156: 569521 cycles: > > 131633 QString::endsWith (/usr/lib/libQt5Core.so.5.8.0) > > 1a0701 QDir::cleanPath (/usr/lib/libQt5Core.so.5.8.0) > > 21b82d [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 1b3727 QFileInfo::canonicalFilePath (/usr/lib/libQt5Core.so.5.8.0) > > 2780c7 QFactoryLoader::update (/usr/lib/libQt5Core.so.5.8.0) > > 279525 QFactoryLoader::QFactoryLoader (/usr/lib/libQt5Core.so.5.8.0) > > e5bd0 QPlatformIntegrationFactory::create (/usr/lib/libQt5Gui.so.5.8.0) > > f5a1c QGuiApplicationPrivate::createPlatformIntegration (/usr/lib/libQt5Gui.so.5.8.0) > > f650c QGuiApplicationPrivate::createEventDispatcher (/usr/lib/libQt5Gui.so.5.8.0) > > 298524 QCoreApplicationPrivate::init (/usr/lib/libQt5Core.so.5.8.0) > > f7cde QGuiApplicationPrivate::init (/usr/lib/libQt5Gui.so.5.8.0) > > 1589e8 QApplicationPrivate::init (/usr/lib/libQt5Widgets.so.5.8.0) > > 78622 main (/home/milian/projects/compiled/other/bin/heaptrack_gui) > > 20439 __libc_start_main (/usr/lib/libc-2.25.so) > > 78299 _start (/home/milian/projects/compiled/other/bin/heaptrack_gui) > > ~~~~~ > > > > Note the two frames 1589e8 and 78622 in the first sample. These are > > missing when unwinding with libdw. The second sample's breakage is > > more obvious: > > > > ~~~~~ > > heaptrack_gui 2228 135073.400474: 613969 cycles: > > 108c8e [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 1093bc [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 109e7b QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) > > 1470ff [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 147f67 QSystemLocale::query (/usr/lib/libQt5Core.so.5.8.0) > > 109fbf QLocalePrivate::updateSystemPrivate (/usr/lib/libQt5Core.so.5.8.0) > > 10aa27 QLocale::QLocale (/usr/lib/libQt5Core.so.5.8.0) > > 1e02c3 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 2113bb [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 211505 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 1b5df0 QFileInfo::exists (/usr/lib/libQt5Core.so.5.8.0) > > 92eb2 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 93423 [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 93d2a QLibraryInfo::location (/usr/lib/libQt5Core.so.5.8.0) > > 2170af [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 297c53 QCoreApplicationPrivate::init (/usr/lib/libQt5Core.so.5.8.0) > > f7cde QGuiApplicationPrivate::init (/usr/lib/libQt5Gui.so.5.8.0) > > 20439 __libc_start_main (/usr/lib/libc-2.25.so) > > 78299 _start (/home/milian/projects/compiled/other/bin/heaptrack_gui) > > > > heaptrack_gui 2228 135073.401156: 569521 cycles: > > 131633 QString::endsWith (/usr/lib/libQt5Core.so.5.8.0) > > 1a0701 QDir::cleanPath (/usr/lib/libQt5Core.so.5.8.0) > > 21b82d [unknown] (/usr/lib/libQt5Core.so.5.8.0) > > 1b3727 QFileInfo::canonicalFilePath (/usr/lib/libQt5Core.so.5.8.0) > > 2780c7 QFactoryLoader::update (/usr/lib/libQt5Core.so.5.8.0) > > 279525 QFactoryLoader::QFactoryLoader (/usr/lib/libQt5Core.so.5.8.0) > > e5bd0 QPlatformIntegrationFactory::create (/usr/lib/libQt5Gui.so.5.8.0) > > 723dbf [unknown] ([unknown]) > > ~~~~~ > > > > This patch fixes this issue and the libdw unwinder mimicks the > > libunwind behavior more closely. > > > > Cc: Arnaldo Carvalho de Melo > > Cc: Namhyung Kim > > Cc: Jiri Olsa > > Signed-off-by: Milian Wolff > > --- > > tools/perf/util/unwind-libdw.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c > > index da45c4be5fb3..7755a5e0fe5e 100644 > > --- a/tools/perf/util/unwind-libdw.c > > +++ b/tools/perf/util/unwind-libdw.c > > @@ -178,6 +178,14 @@ frame_callback(Dwfl_Frame *state, void *arg) > > Dwarf_Addr pc; > > bool isactivation; > > > > + if (!dwfl_frame_pc(state, &pc, NULL)) { > > + pr_err("%s", dwfl_errmsg(-1)); > > + return DWARF_CB_ABORT; > > + } > > + > > + // report the module before we query for isactivation > > + report_module(pc, ui); > > + > > if (!dwfl_frame_pc(state, &pc, &isactivation)) { > > pr_err("%s", dwfl_errmsg(-1)); > > return DWARF_CB_ABORT; > > -- > > 2.13.0