> On Sept. 9, 2014, 9:04 a.m., David Edmundson wrote: > > src/declarativeimports/core/datasource.cpp, line 171 > > <https://git.reviewboard.kde.org/r/120110/diff/1/?file=310511#file310511line171> > > > > Nice work identifying the cause, but I think we can improve the fix. > > > > We were calling this lambda after the datasource object is deleted so > > this (and therefore m_models) is pointing to random memory, we just happen > > to be resetting the random memory to zero just beforehand, but it's not a > > fix that is going to work for long. > > > > It's interesting that there's a model that outlives the datasource, > > that implies a buggy datasource somewhere... but we need to fix this too. > > > > It could be solved by using a normal slot so we get automatic > > disconnect wheh the receiver is destroyed. > > > > Can probably be done with better lambdas but I don't know how. > > Joseph Wenninger wrote: > With a traditional slot the model has to have a property telling it's > sourcename or we need a second inverse map. If I'm not mistaken, > QQMLPropertyMap does not allow lookups or item removals by the value, but > only by key. The first solution makes it more difficult for users of the API, > the second solution isn't that nice either. What would be your idea to keep > track of the sourcename for a model being deleted.
Just discussed in real life, came up with the correct patch where the lambda auto disconnects (thanks Aleix) - David ----------------------------------------------------------- This is an automatically generated e-mail. To reply, visit: https://git.reviewboard.kde.org/r/120110/#review66098 ----------------------------------------------------------- On Sept. 9, 2014, 10:38 a.m., Joseph Wenninger wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://git.reviewboard.kde.org/r/120110/ > ----------------------------------------------------------- > > (Updated Sept. 9, 2014, 10:38 a.m.) > > > Review request for KDE Frameworks and Plasma. > > > Repository: plasma-framework > > > Description > ------- > > Fix a crash when shutting down plasma shell, while destruction models > > > While porting the kate session applet to plasma KF5, I noticed plasmashell > crashing while using "kquitapp5 plasmashell" while destroying the model in > the clipboard engine and in my engine (which is based on the clipboard > engine). > > The problem for me was, that the lambda in Plasma::DataEngine:167 accessed > m_models, which was/is not valid anymore. > > Thread 1 (Thread 0x7f2f4cadb880 (LWP 4241)): > [KCrash Handler] > #6 0x00007f2f488336df in QQmlOpenMetaObject::setValue(QByteArray const&, > QVariant const&) () from /home/jowenn/KDE/qt5/qtbase/lib/libQt5Qml.so.5 > #7 0x00007f2f486c6d14 in QQmlPropertyMap::clear(QString const&) () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Qml.so.5 > #8 0x00007f2f2dfb94e4 in Plasma::DataSource::<lambda()>::operator()(void) > const (__closure=0x7fffb8e86670) at > /home/jowenn/KDE/kf5/src/frameworks/plasma-framework/src/declarativeimports/core/datasource.cpp:167 > #9 0x00007f2f2dfb9b88 in QtPrivate::FunctorCall<QtPrivate::IndexesList<>, > QtPrivate::List<>, void, Plasma::DataSource::modelChanged(const QString&, > QAbstractItemModel*)::<lambda()> >::call(Plasma::DataSource::<lambda()>, void > **) (f=..., arg=0x7fffb8e86800) at > /home/jowenn/KDE/qt5/qtbase/src/corelib/kernel/qobjectdefs_impl.h:502 > #10 0x00007f2f2dfb9b5e in > QtPrivate::Functor<Plasma::DataSource::modelChanged(const QString&, > QAbstractItemModel*)::<lambda()>, 0>::call<QtPrivate::List<>, > void>(Plasma::DataSource::<lambda()> &, void *, void **) (f=..., > arg=0x7fffb8e86800) at > /home/jowenn/KDE/qt5/qtbase/src/corelib/kernel/qobjectdefs_impl.h:559 > #11 0x00007f2f2dfb9b13 in > QtPrivate::QFunctorSlotObject<Plasma::DataSource::modelChanged(const > QString&, QAbstractItemModel*)::<lambda()>, 0, QtPrivate::List<>, > void>::impl(int, QtPrivate::QSlotObjectBase *, QObject *, void **, bool *) > (which=1, this_=0x56aee80, r=0x5776340, a=0x7fffb8e86800, ret=0x0) at > /home/jowenn/KDE/qt5/qtbase/src/corelib/kernel/qobject_impl.h:200 > #12 0x00007f2f459656be in QMetaObject::activate(QObject*, int, int, void**) > () from /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #13 0x00007f2f4596609f in QObject::destroyed(QObject*) () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #14 0x00007f2f4596d70b in QObject::~QObject() () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #15 0x00007f2f458ddd1d in QAbstractItemModel::~QAbstractItemModel() () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #16 0x00007f2e401af49e in KateSessionsModel::~KateSessionsModel > (this=0x5776340, __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/kde/applications/kate/addons/sessionapplet/engine/katesessionsmodel.cpp:59 > #17 0x00007f2e401af4ce in KateSessionsModel::~KateSessionsModel > (this=0x5776340, __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/kde/applications/kate/addons/sessionapplet/engine/katesessionsmodel.cpp:61 > #18 0x00007f2f4596460c in QObjectPrivate::deleteChildren() () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #19 0x00007f2f4596d493 in QObject::~QObject() () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #20 0x00007f2f4b644e47 in Plasma::DataContainer::~DataContainer > (this=0x5775ef0, __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/frameworks/plasma-framework/src/plasma/datacontainer.cpp:37 > #21 0x00007f2f4b644e76 in Plasma::DataContainer::~DataContainer > (this=0x5775ef0, __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/frameworks/plasma-framework/src/plasma/datacontainer.cpp:40 > #22 0x00007f2f4596460c in QObjectPrivate::deleteChildren() () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #23 0x00007f2f4596d493 in QObject::~QObject() () from > /home/jowenn/KDE/qt5/qtbase/lib/libQt5Core.so.5 > #24 0x00007f2f4b648c21 in Plasma::DataEngine::~DataEngine (this=0x5774b50, > __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/frameworks/plasma-framework/src/plasma/dataengine.cpp:76 > #25 0x00007f2e401ae418 in KateSessionsEngine::~KateSessionsEngine > (this=0x5774b50, __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/kde/applications/kate/addons/sessionapplet/engine/katesessionsengine.cpp:36 > #26 0x00007f2e401ae448 in KateSessionsEngine::~KateSessionsEngine > (this=0x5774b50, __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/kde/applications/kate/addons/sessionapplet/engine/katesessionsengine.cpp:38 > #27 0x00007f2f4b65133d in Plasma::DataEngineManager::unloadEngine > (this=0x7f2f4b8dc7c0 <Plasma::(anonymous > namespace)::Q_QGS_privateDataEngineManagerSelf::innerFunction()::holder>, > name=...) at > /home/jowenn/KDE/kf5/src/frameworks/plasma-framework/src/plasma/private/dataenginemanager.cpp:159 > #28 0x00007f2f4b64cc6d in Plasma::DataEngineConsumer::~DataEngineConsumer > (this=0x552c070, __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/frameworks/plasma-framework/src/plasma/dataengineconsumer.cpp:85 > #29 0x00007f2f2dfa523a in Plasma::DataSource::~DataSource (this=0x552c060, > __in_chrg=<optimized out>) at > /home/jowenn/KDE/kf5/src/frameworks/plasma-framework/src/declarativeimports/core/datasource.h:43 > #30 0x00007f2f2dfac8b8 in > QQmlPrivate::QQmlElement<Plasma::DataSource>::~QQmlElement (this=0x552c060, > __in_chrg=<optimized out>) at > /home/jowenn/KDE/qt5/qtdeclarative/src/qml/qml/qqmlprivate.h:106 > #31 0x00007f2f2dfac8e8 in > QQmlPrivate::QQmlElement<Plasma::DataSource>::~QQmlElement (this=0x552c060, > __in_chrg=<optimized out>) at > /home/jowenn/KDE/qt5/qtdeclarative/src/qml/qml/qqmlprivate.h:106 > > > Diffs > ----- > > src/declarativeimports/core/datasource.h > 3a8b522919f04f8581e98271aff55ccc001062c8 > src/declarativeimports/core/datasource.cpp > 2e7a2af4919f85bb385e95f2a29f9cdb5e7ecfda > > Diff: https://git.reviewboard.kde.org/r/120110/diff/ > > > Testing > ------- > > This part of plasma shell does not cause a crash for me anymore. > > > Thanks, > > Joseph Wenninger > >
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