Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752167AbdFPTkG (ORCPT ); Fri, 16 Jun 2017 15:40:06 -0400 Received: from terminus.zytor.com ([65.50.211.136]:45863 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751667AbdFPTkE (ORCPT ); Fri, 16 Jun 2017 15:40:04 -0400 Date: Fri, 16 Jun 2017 12:38:44 -0700 From: tip-bot for Milian Wolff Message-ID: Cc: jolsa@redhat.com, mingo@kernel.org, jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org, hpa@zytor.com, milian.wolff@kdab.com, tglx@linutronix.de, acme@redhat.com, namhyung@kernel.org Reply-To: acme@redhat.com, namhyung@kernel.org, tglx@linutronix.de, milian.wolff@kdab.com, hpa@zytor.com, jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org, jolsa@redhat.com, mingo@kernel.org In-Reply-To: <20170602143753.16907-2-milian.wolff@kdab.com> References: <20170602143753.16907-2-milian.wolff@kdab.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf unwind: Report module before querying isactivation in dwfl unwind Git-Commit-ID: 9126cbbacecb8917bd0418809ef1d26616b2061e X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6584 Lines: 128 Commit-ID: 9126cbbacecb8917bd0418809ef1d26616b2061e Gitweb: http://git.kernel.org/tip/9126cbbacecb8917bd0418809ef1d26616b2061e Author: Milian Wolff AuthorDate: Fri, 2 Jun 2017 16:37:53 +0200 Committer: Arnaldo Carvalho de Melo CommitDate: Fri, 16 Jun 2017 14:37:30 -0300 perf unwind: Report module before querying isactivation in dwfl unwind 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.: ~~~~~ 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. Signed-off-by: Milian Wolff Acked-by: Jan Kratochvil Cc: Jiri Olsa Cc: Namhyung Kim Link: http://lkml.kernel.org/r/20170602143753.16907-2-milian.wolff@kdab.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 da45c4b..7755a5e0 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;