Details
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Bug
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Resolution: Invalid
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Not Evaluated
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None
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5.3.0
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None
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Linux, X11, helgrind
Description
Calling sessionBus() in multiple threads simultaneously leads to
==16679== Possible data race during read of size 8 at 0x8220AE0 by thread #2 ==16679== Locks held: none ==16679== at 0x7F8EAF8: QDBusConnection::QDBusConnection(QDBusConnection const&) (qdbusconnection.cpp:268) ==16679== by 0x7F90BA1: QDBusConnection::sessionBus() (qdbusconnection.cpp:1092) ==16679== ==16679== This conflicts with a previous write of size 8 by thread #3 ==16679== Locks held: 1, at address 0x8220A80 ==16679== at 0x7F8EAFF: QDBusConnection::QDBusConnection(QDBusConnection const&) (qdbusconnection.cpp:268) ==16679== by 0x7F8EE07: QDBusConnection::connectToBus(QDBusConnection::BusType, QString const&) (qdbusconnection.cpp:355) ==16679== by 0x7F91D06: QDBusDefaultConnection::QDBusDefaultConnection(QDBusConnection::BusType, char const*) (qdbusconnection.cpp:1062) ==16679== by 0x7F909CF: (anonymous namespace)::Q_QGS__q_sessionBus::innerFunction()::Holder::Holder() (qdbusconnection.cpp:1078) ==16679== by 0x7F90A3C: (anonymous namespace)::Q_QGS__q_sessionBus::innerFunction() (qdbusconnection.cpp:1078) ==16679== by 0x7F90D6D: QGlobalStatic<[...]>::operator()() (qglobalstatic.h:128) ==16679== by 0x7F90B8F: QDBusConnection::sessionBus() (qdbusconnection.cpp:1092)
The guilty line of code is
d = other.d;
in the QDBusConnection copy constructor.
It is not documented as thread-safe, does this mean that this is not a bug?
In that case, we do need something like KDE's KDBusConnectionPool in Qt...
The problem is that there are more races, when using sessionBus() in multiple threads...
==16679== Possible data race during read of size 8 at 0xF57F3B8 by thread #2 ==16679== Locks held: none ==16679== at 0x7F8FEE4: QDBusConnection::registerObject(QString const&, QObject*, QFlags<QDBusConnection::RegisterOption>) (qdbusconnection.cpp:787) ==16679== This conflicts with a previous write of size 8 by thread #3 ==16679== Locks held: 1, at address 0x8220A80 ==16679== at 0x7FA0215: QDBusConnectionPrivate::setConnection(DBusConnection*, QDBusErrorInternal const&) (qdbusintegrator.cpp:1763) ==16679== by 0x7F8EDAF: QDBusConnection::connectToBus(QDBusConnection::BusType, QString const&) (qdbusconnection.cpp:345)
Attachments
Issue Links
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- Closed
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