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Milian Wolff 9126cbbace 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 <milian.wolff@kdab.com>
Acked-by: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20170602143753.16907-2-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
 		2017-06-16 14:37:30 -03:00
..
Documentation perf script python: Remove dups in documentation examples 2017-06-07 20:36:12 -03:00
arch perf tools: Fix build with ARCH=x86_64 2017-06-14 15:44:29 -03:00
bench perf tools: Move extra string util functions to util/string2.h 2017-04-19 13:01:51 -03:00
jvmti perf kvmti: Remove unused Makefile file 2016-11-14 12:42:56 -03:00
pmu-events perf tools: Fix build with ARCH=x86_64 2017-06-14 15:44:29 -03:00
python perf python: Add tracepoint example 2016-07-12 16:23:35 -03:00
scripts perf/core improvements and fixes: 2016-08-04 11:02:38 +02:00
tests perf tools: Fix build with ARCH=x86_64 2017-06-14 15:44:29 -03:00
trace perf tools: Add signal.h to places using its definitions 2017-04-20 13:22:43 -03:00
ui perf tools: Put caller above callee in --children mode 2017-05-24 08:41:49 +02:00
util perf unwind: Report module before querying isactivation in dwfl unwind 2017-06-16 14:37:30 -03:00
.gitignore perf tools: Ignore generated files pmu-events/{jevents,pmu-events.c} for git 2017-03-13 10:59:36 -03:00
Build perf trace: Beautify statx syscall 'flag' and 'mask' arguments 2017-03-31 14:42:31 -03:00
CREDITS
…
MANIFEST tools include: Introduce linux/bug.h, from the kernel sources 2017-04-19 13:01:42 -03:00
Makefile
…
Makefile.config perf tools: Fix build with ARCH=x86_64 2017-06-14 15:44:29 -03:00
Makefile.perf perf tools: Fix build with ARCH=x86_64 2017-06-14 15:44:29 -03:00
builtin-annotate.c perf tools: Include errno.h where needed 2017-04-19 13:01:51 -03:00
builtin-bench.c perf tools: Remove unused 'prefix' from builtin functions 2017-03-27 11:58:09 -03:00
builtin-buildid-cache.c perf symbols: Accept symbols starting at address 0 2017-05-02 18:23:04 -03:00
builtin-buildid-list.c perf tools: Include errno.h where needed 2017-04-19 13:01:51 -03:00
builtin-c2c.c perf tools: Move event prototypes from util.h to event.h 2017-04-25 15:30:47 -03:00
builtin-config.c perf config: Refactor a duplicated code for obtaining config file name 2017-05-02 18:23:12 -03:00
builtin-data.c perf tools: Remove unused 'prefix' from builtin functions 2017-03-27 11:58:09 -03:00
builtin-diff.c perf tools: Include errno.h where needed 2017-04-19 13:01:51 -03:00
builtin-evlist.c perf tools: Remove unused 'prefix' from builtin functions 2017-03-27 11:58:09 -03:00
builtin-ftrace.c perf tools: Remove poll.h and wait.h from util.h 2017-04-24 13:43:34 -03:00
builtin-help.c perf tools: Remove string.h, unistd.h and sys/stat.h from util.h 2017-04-24 13:43:33 -03:00
builtin-inject.c perf tools: Use just forward declarations for struct thread where possible 2017-04-24 13:43:35 -03:00
builtin-kallsyms.c perf tools: Including missing inttypes.h header 2017-04-19 13:01:46 -03:00
builtin-kmem.c perf tools: Include errno.h where needed 2017-04-19 13:01:51 -03:00
builtin-kvm.c perf tools: Remove poll.h and wait.h from util.h 2017-04-24 13:43:34 -03:00
builtin-list.c perf tools: Remove unused 'prefix' from builtin functions 2017-03-27 11:58:09 -03:00
builtin-lock.c perf tools: Include errno.h where needed 2017-04-19 13:01:51 -03:00
builtin-mem.c perf tools: Use just forward declarations for struct thread where possible 2017-04-24 13:43:35 -03:00
builtin-probe.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2017-05-02 19:09:35 -07:00
builtin-record.c perf tools: Remove poll.h and wait.h from util.h 2017-04-24 13:43:34 -03:00
builtin-report.c perf tools: Remove string.h, unistd.h and sys/stat.h from util.h 2017-04-24 13:43:33 -03:00
builtin-sched.c perf tools: Include errno.h where needed 2017-04-19 13:01:51 -03:00
builtin-script.c perf script: Add --inline option for debugging 2017-05-24 08:41:48 +02:00
builtin-stat.c perf stat: Only print NMI watchdog hint when enabled 2017-06-02 11:15:34 -03:00
builtin-timechart.c perf tools: Use just forward declarations for struct thread where possible 2017-04-24 13:43:35 -03:00
builtin-top.c perf tools: Move event prototypes from util.h to event.h 2017-04-25 15:30:47 -03:00
builtin-trace.c perf trace: Add mmap alias for s390 2017-06-01 10:13:21 -03:00
builtin-version.c perf tools: Remove string.h, unistd.h and sys/stat.h from util.h 2017-04-24 13:43:33 -03:00
builtin.h perf tools: Remove stale prototypes from builtin.h 2017-04-24 13:43:33 -03:00
check-headers.sh tools include uapi: Grab copies of stat.h and fcntl.h 2017-03-31 11:26:03 -03:00
command-list.txt perf tools: Missing c2c command in command-list 2017-03-13 10:59:31 -03:00
design.txt
…
perf-archive.sh
…
perf-completion.sh
…
perf-read-vdso.c
…
perf-sys.h perf powerpc: Fix build-test failure 2016-09-08 13:44:07 -03:00
perf-with-kcore.sh
…
perf.c perf tools: Move event prototypes from util.h to event.h 2017-04-25 15:30:47 -03:00
perf.h perf tools: Add PERF_RECORD_NAMESPACES to include namespaces related info 2017-03-14 11:38:23 -03:00