From ebf0b121084822ce754c14ed7255bde0f90bf42f Mon Sep 17 00:00:00 2001 From: Thiago Macieira Date: Tue, 6 Sep 2016 11:41:00 -0700 Subject: Make QDBusConnectionPrivate::relaySignal be called in the right thread This function sends D-Bus messages directly (in huntAndEmit), so it should only be called from the QDBusConnectionManager thread. Somehow, I missed this in the Qt 5.6 refactoring of QtDBus. Being called in the wrong thread means that there's a visible behavior change compared to Qt 5.5: if the user code sent a method call or method return/error and then emitted a signal, we'd have two threads racing to send the D-Bus messages. This was observed in Telepathy-Qt code: certain signals arrived before a method return, even though they were clearly emitted by a queued QMetaObject::invokeMethod. In addition to that, we have has an internal problem (though not observed): the libdbus-1 timer and socket callbacks would be called in the wrong thread and we no longer have protection against that. Unit testing not possible since this is a race condition. Change-Id: I9e96ecd4f6aa4ff0ae08fffd1471d002142613d6 Reviewed-by: Gustavo Pichorim Boiko Reviewed-by: Alex Blasche --- src/dbus/qdbusintegrator.cpp | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'src/dbus') diff --git a/src/dbus/qdbusintegrator.cpp b/src/dbus/qdbusintegrator.cpp index 878a58294c..c2cf7f41e4 100644 --- a/src/dbus/qdbusintegrator.cpp +++ b/src/dbus/qdbusintegrator.cpp @@ -1257,6 +1257,7 @@ void QDBusConnectionPrivate::relaySignal(QObject *obj, const QMetaObject *mo, in break; } + checkThread(); QDBusReadLocker locker(RelaySignalAction, this); QDBusMessage message = QDBusMessage::createSignal(QLatin1String("/"), interface, QLatin1String(memberName)); @@ -2368,12 +2369,9 @@ void QDBusConnectionPrivate::registerObject(const ObjectTreeNode *node) connector->connectAllSignals(node->obj); } - // disconnect and reconnect to avoid duplicates - connector->disconnect(SIGNAL(relaySignal(QObject*,const QMetaObject*,int,QVariantList)), - this, SLOT(relaySignal(QObject*,const QMetaObject*,int,QVariantList))); connect(connector, SIGNAL(relaySignal(QObject*,const QMetaObject*,int,QVariantList)), this, SLOT(relaySignal(QObject*,const QMetaObject*,int,QVariantList)), - Qt::DirectConnection); + Qt::ConnectionType(Qt::QueuedConnection | Qt::UniqueConnection)); } } -- cgit v1.2.3