Review Request 125613: Race condition and error notification loss in ListJob
Aleix Pol Gonzalez
aleixpol at kde.org
Mon Oct 26 17:27:39 GMT 2015
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https://git.reviewboard.kde.org/r/125613/#review87445
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This patch introduced a crash here. Could you maybe look into it? Here's a backtrace.
It happens on some (not all) programs when the open dialog is displayed. I can reproduce it with ksnapshot and kdevelop, but not with Kate.
```
(gdb) where
#0 0x00007ffff22925f8 in raise () from /usr/lib/libc.so.6
#1 0x00007ffff2293a7a in abort () from /usr/lib/libc.so.6
#2 0x00007ffff2f3205e in qt_message_fatal (context=..., message=<synthetic pointer>) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/global/qlogging.cpp:1610
#3 QMessageLogger::fatal (this=this at entry=0x7fffffffc070, msg=msg at entry=0x7ffff31e57f0 "ASSERT: \"%s\" in file %s, line %d") at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/global/qlogging.cpp:784
#4 0x00007ffff2f2d5de in qt_assert (assertion=<optimized out>, file=<optimized out>, line=<optimized out>) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/global/qglobal.cpp:3046
#5 0x00007ffff63fb097 in KCoreDirListerCache::slotResult (this=0x7ffff669b840 <(anonymous namespace)::Q_QGS_kDirListerCache::innerFunction()::holder>, j=0xe972b0) at /home/kde-devel/frameworks/kio/src/core/kcoredirlister.cpp:1310
#6 0x00007ffff6404e41 in KCoreDirListerCache::qt_static_metacall (_o=0x7ffff669b840 <(anonymous namespace)::Q_QGS_kDirListerCache::innerFunction()::holder>, _c=QMetaObject::InvokeMetaMethod, _id=8, _a=0x7fffffffc390) at src/core/moc_kcoredirlister_p.cpp:133
#7 0x00007ffff314ae6a in QMetaObject::activate (sender=0xe972b0, signalOffset=<optimized out>, local_signal_index=<optimized out>, argv=<optimized out>) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qobject.cpp:3730
#8 0x00007ffff4742f9b in KJob::result (this=0xe972b0, _t1=0xe972b0) at src/lib/moc_kjob.cpp:555
#9 0x00007ffff47419f1 in KJob::emitResult (this=0xe972b0) at /home/kde-devel/frameworks/kcoreaddons/src/lib/jobs/kjob.cpp:294
#10 0x00007ffff47412e4 in KJob::kill (this=0xe972b0, verbosity=KJob::EmitResult) at /home/kde-devel/frameworks/kcoreaddons/src/lib/jobs/kjob.cpp:103
#11 0x00007ffff63f6473 in KCoreDirListerCache::stopListJob (this=0x7ffff669b840 <(anonymous namespace)::Q_QGS_kDirListerCache::innerFunction()::holder>, url="file:///home/apol/Documents", silent=true) at /home/kde-devel/frameworks/kio/src/core/kcoredirlister.cpp:493
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#12 0x00007ffff63f6364 in KCoreDirListerCache::stopListingUrl (this=0x7ffff669b840 <(anonymous namespace)::Q_QGS_kDirListerCache::innerFunction()::holder>, lister=0x9ef910, _u=, silent=true) at /home/kde-devel/frameworks/kio/src/core/kcoredirlister.cpp:463
#13 0x00007ffff63f613a in KCoreDirListerCache::stop (this=0x7ffff669b840 <(anonymous namespace)::Q_QGS_kDirListerCache::innerFunction()::holder>, lister=0x9ef910, silent=true) at /home/kde-devel/frameworks/kio/src/core/kcoredirlister.cpp:421
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#14 0x00007ffff63f4ea1 in KCoreDirListerCache::listDir (this=0x7ffff669b840 <(anonymous namespace)::Q_QGS_kDirListerCache::innerFunction()::holder>, lister=0x9ef910, _u=, _keep=false, _reload=false) at /home/kde-devel/frameworks/kio/src/core/kcoredirlister.cpp:143
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#15 0x00007ffff6400fa0 in KCoreDirLister::openUrl (this=0x9ef910, _url=, _flags=...) at /home/kde-devel/frameworks/kio/src/core/kcoredirlister.cpp:2151
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#16 0x00007fffe61e1342 in KDirOperator::Private::openUrl (this=0x9f2ff0, url=, flags=...) at /home/kde-devel/frameworks/kio/src/filewidgets/kdiroperator.cpp:1069
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#17 0x00007fffe61e1218 in KDirOperator::setUrl (this=0x9ee560, _newurl=, clearforward=true) at /home/kde-devel/frameworks/kio/src/filewidgets/kdiroperator.cpp:1051
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#18 0x00007fffe6204b8c in KFileWidget::setUrl (this=0x89a500, url=, clearforward=true) at /home/kde-devel/frameworks/kio/src/filewidgets/kfilewidget.cpp:1460
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#19 0x00007fffe64a82c8 in KDEPlatformFileDialog::setDirectory (this=0x869a90, directory=) at /home/kde-devel/frameworks/frameworkintegration/src/platformtheme/kdeplatformfiledialoghelper.cpp:189
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#20 0x00007fffe64a933e in KDEPlatformFileDialogHelper::setDirectory (this=0x877040, directory=) at /home/kde-devel/frameworks/frameworkintegration/src/platformtheme/kdeplatformfiledialoghelper.cpp:352
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#21 0x00007ffff3c8978b in QFileDialogPrivate::setDirectory_sys (directory=, this=<optimized out>) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/dialogs/qfiledialog_p.h:368
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#22 QFileDialog::setDirectoryUrl (this=this at entry=0x7fffffffccb0, directory=) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/dialogs/qfiledialog.cpp:976
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#23 0x00007ffff3c96988 in QFileDialogPrivate::init (this=0x87caf0, directory=,
nameFilter=";;Windows BMP image (*.bmp *.dib);;JPEG-2000 image (*.jp2 *.jpx *.jpf);;JPEG Image (*.jpeg *.jpg *.jpe *.jfif);;PNG image (*.png);;TIFF image (*.tif *.tiff);;Windows icon (*.ico);;WBMP image (*.wbmp);;"..., caption="Save Snapshot As")
at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/dialogs/qfiledialog.cpp:2804
#24 0x00007ffff3c96e66 in QFileDialog::QFileDialog (this=0x7fffffffccb0, args=...) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/dialogs/qfiledialog.cpp:373
Python Exception <class 'gdb.error'> cannot resolve overloaded method `data': no arguments supplied:
#25 0x00007ffff3c9789b in QFileDialog::getSaveFileUrl (parent=0x7fffffffdce0, caption="Save Snapshot As", dir=,
filter=";;Windows BMP image (*.bmp *.dib);;JPEG-2000 image (*.jp2 *.jpx *.jpf);;JPEG Image (*.jpeg *.jpg *.jpe *.jfif);;PNG image (*.png);;TIFF image (*.tif *.tiff);;Windows icon (*.ico);;WBMP image (*.wbmp);;"..., selectedFilter=0x7fffffffcd90, options=...,
supportedSchemes=empty QStringList<QString>) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/dialogs/qfiledialog.cpp:2387
#26 0x000000000043995d in KSnapshot::slotSaveAs (this=0x7fffffffdce0) at /home/kde-devel/frameworks/ksnapshot/ksnapshot.cpp:347
#27 0x0000000000443ca3 in QtPrivate::FunctorCall<QtPrivate::IndexesList<>, QtPrivate::List<>, void, void (KSnapshot::*)()>::call(void (KSnapshot::*)(), KSnapshot*, void**) (f=(void (KSnapshot::*)(KSnapshot * const)) 0x4396ac <KSnapshot::slotSaveAs()>, o=0x7fffffffdce0,
arg=0x7fffffffd050) at /home/kde-devel/kde5/include/QtCore/qobjectdefs_impl.h:501
#28 0x0000000000443623 in QtPrivate::FunctionPointer<void (KSnapshot::*)()>::call<QtPrivate::List<>, void>(void (KSnapshot::*)(), KSnapshot*, void**) (f=(void (KSnapshot::*)(KSnapshot * const)) 0x4396ac <KSnapshot::slotSaveAs()>, o=0x7fffffffdce0, arg=0x7fffffffd050)
at /home/kde-devel/kde5/include/QtCore/qobjectdefs_impl.h:520
#29 0x0000000000442b03 in QtPrivate::QSlotObject<void (KSnapshot::*)(), QtPrivate::List<>, void>::impl(int, QtPrivate::QSlotObjectBase*, QObject*, void**, bool*) (which=1, this_=0x8c4c10, r=0x7fffffffdce0, a=0x7fffffffd050, ret=0x0)
at /home/kde-devel/kde5/include/QtCore/qobject_impl.h:143
#30 0x00007ffff314acf7 in QtPrivate::QSlotObjectBase::call (a=0x7fffffffd050, r=0x7fffffffdce0, this=<optimized out>) at ../../include/QtCore/../../../../frameworks/qt5/qtbase/src/corelib/kernel/qobject_impl.h:124
#31 QMetaObject::activate (sender=sender at entry=0x8c1fc0, signalOffset=<optimized out>, local_signal_index=local_signal_index at entry=2, argv=argv at entry=0x7fffffffd050) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qobject.cpp:3715
#32 0x00007ffff314b667 in QMetaObject::activate (sender=sender at entry=0x8c1fc0, m=m at entry=0x7ffff3f99000 <QAbstractButton::staticMetaObject>, local_signal_index=local_signal_index at entry=2, argv=argv at entry=0x7fffffffd050)
at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qobject.cpp:3595
#33 0x00007ffff3e0f372 in QAbstractButton::clicked (this=this at entry=0x8c1fc0, _t1=false) at .moc/moc_qabstractbutton.cpp:303
#34 0x00007ffff3b8e654 in QAbstractButtonPrivate::emitClicked (this=0x8c27e0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/widgets/qabstractbutton.cpp:533
#35 0x00007ffff3b8fb29 in QAbstractButtonPrivate::click (this=0x8c27e0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/widgets/qabstractbutton.cpp:526
#36 0x00007ffff3b8fc7c in QAbstractButton::mouseReleaseEvent (this=0x8c1fc0, e=0x7fffffffd4e0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/widgets/qabstractbutton.cpp:1131
#37 0x00007ffff3af3588 in QWidget::event (this=0x8c1fc0, event=0x7fffffffd4e0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qwidget.cpp:9064
#38 0x00007ffff3ab2dcc in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x8c1fc0, e=0x7fffffffd4e0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3717
#39 0x00007ffff3ab88ce in QApplication::notify (this=<optimized out>, receiver=0x8c1fc0, e=0x7fffffffd4e0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3275
#40 0x00007ffff311d2d8 in QCoreApplication::notifyInternal2 (receiver=receiver at entry=0x8c1fc0, event=event at entry=0x7fffffffd4e0) at /home/kde-devel/frameworks/qt5/qtbase/src/corelib/kernel/qcoreapplication.cpp:1002
#41 0x00007ffff3ab745e in QCoreApplication::sendSpontaneousEvent (event=0x7fffffffd4e0, receiver=0x8c1fc0) at ../../include/QtCore/../../../../frameworks/qt5/qtbase/src/corelib/kernel/qcoreapplication.h:230
#42 QApplicationPrivate::sendMouseEvent (receiver=receiver at entry=0x8c1fc0, event=event at entry=0x7fffffffd4e0, alienWidget=alienWidget at entry=0x8c1fc0, nativeWidget=0x7fffffffdce0, buttonDown=buttonDown at entry=0x7ffff3fa4ba0 <qt_button_down>, lastMouseReceiver=...,
spontaneous=true) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qapplication.cpp:2770
#43 0x00007ffff3b0daa1 in QWidgetWindow::handleMouseEvent (this=this at entry=0x7be360, event=event at entry=0x7fffffffd8f0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qwidgetwindow.cpp:554
#44 0x00007ffff3b0fe7b in QWidgetWindow::event (this=0x7be360, event=0x7fffffffd8f0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qwidgetwindow.cpp:210
#45 0x00007ffff3ab2dcc in QApplicationPrivate::notify_helper (this=<optimized out>, receiver=0x7be360, e=0x7fffffffd8f0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3717
#46 0x00007ffff3ab7d96 in QApplication::notify (this=0x7fffffffde80, receiver=0x7be360, e=0x7fffffffd8f0) at /home/kde-devel/frameworks/qt5/qtbase/src/widgets/kernel/qapplication.cpp:3498
```
- Aleix Pol Gonzalez
On Oct. 24, 2015, 7:54 p.m., Alberto Jiménez Ruiz wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/125613/
> -----------------------------------------------------------
>
> (Updated Oct. 24, 2015, 7:54 p.m.)
>
>
> Review request for kdelibs, Albert Astals Cid and David Faure.
>
>
> Bugs: 333436
> http://bugs.kde.org/show_bug.cgi?id=333436
>
>
> Repository: kdelibs
>
>
> Description
> -------
>
> Race condition and error notification loss in ListJob
>
>
> Diffs
> -----
>
> kio/kio/job.cpp 91712e3
> kio/kio/jobclasses.h d771cfe
> kio/tests/jobtest.h d3c552e
> kio/tests/jobtest.cpp ee2677a
>
> Diff: https://git.reviewboard.kde.org/r/125613/diff/
>
>
> Testing
> -------
>
> Update 1, added unittest
> Changed condition of listjob slotresult finishing (When executed as a synchronous job, gets stuck in a eventloop)
> Added setError to copyjob.
>
>
> Tests done on Kubuntu 15.10:
>
> With this folder structure in ~:
> src
> ######c (Folder)
> ##############b (Folder chmod'ed to 700 and owned by root)
> #######################d (10MB file made of /dev/urandom data)
> ##############a (10MB file made of /dev/urandom data)
>
> Then, (as a normal user execute: "kioclient ~/src ~/dst")
>
> Expected result: Notification that some files were not able to be copied (Cannot access "b" folder)
> Result with latest kdelibs: Silent copying where b folder is owned by user but nothing inside.
> ---When all kdebugdialog flags are set, a backtrace is also seen.
>
> subError notifications for listjob subjobs are lost, Copyjob uses this signal to skip data.
>
> Also, this fix prevents a race condition.
>
> ListJob has another ListJob as a subjob.
>
> Chaild fails for whatever reason and calls error, which calls slotError, which calls slotsFinished and emitResult.
> The result of the child gets collected by parent. slotResult of parent gets called, removes subjob and emitsresult because there are no subjobs left.
> ---That's fine as long as the slave associated with the parent emits finished before the child fails. If it doesn't, parent calls emitsResult twice.
>
>
> Result after patch: kioclient shows a MessageBox telling the copy operation could not be completed.
>
>
> Thanks,
>
> Alberto Jiménez Ruiz
>
>
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