From b77ef8a7e6e4104067d52824e29eadc8c66f5929 Mon Sep 17 00:00:00 2001 From: Weng Xuetian Date: Sat, 5 Mar 2016 12:23:21 -0800 Subject: QtDBus: clean up signal hooks and object tree in closeConnection If a QObject is added or passed as receiver to QDBusConnection::connect() and it is managed by Q_GLOBAL_STATIC or similar mechanism, it is possible that when that its destructor is called after the dbus daemon thread ends. In that case, QObject::destroyed connected via Qt::BlockingQueuedConnection to QDBusConnectionPrivate will cause dead lock since the thread is no longer processing events. Task-number: QTBUG-51648 Change-Id: I1a1810a6d6d0234af0269d5f3fc1f54101bf1547 Reviewed-by: Thiago Macieira --- src/dbus/qdbusconnection_p.h | 1 + src/dbus/qdbusintegrator.cpp | 26 +++++++++++++++++++++++++- 2 files changed, 26 insertions(+), 1 deletion(-) (limited to 'src/dbus') diff --git a/src/dbus/qdbusconnection_p.h b/src/dbus/qdbusconnection_p.h index c77daf7ee1..565eb832f2 100644 --- a/src/dbus/qdbusconnection_p.h +++ b/src/dbus/qdbusconnection_p.h @@ -254,6 +254,7 @@ private: const QVector &metaTypes, int slotIdx); SignalHookHash::Iterator removeSignalHookNoLock(SignalHookHash::Iterator it); + void disconnectObjectTree(ObjectTreeNode &node); bool isServiceRegisteredByThread(const QString &serviceName); diff --git a/src/dbus/qdbusintegrator.cpp b/src/dbus/qdbusintegrator.cpp index 478a2c4a05..3be775db82 100644 --- a/src/dbus/qdbusintegrator.cpp +++ b/src/dbus/qdbusintegrator.cpp @@ -1050,7 +1050,6 @@ QDBusConnectionPrivate::~QDBusConnectionPrivate() qPrintable(name)); closeConnection(); - rootNode.children.clear(); // free resources qDeleteAll(cachedMetaObjects); if (mode == ClientMode || mode == PeerMode) { @@ -1072,6 +1071,19 @@ QDBusConnectionPrivate::~QDBusConnectionPrivate() } } +void QDBusConnectionPrivate::disconnectObjectTree(QDBusConnectionPrivate::ObjectTreeNode &haystack) +{ + QDBusConnectionPrivate::ObjectTreeNode::DataList::Iterator it = haystack.children.begin(); + + while (it != haystack.children.end()) { + disconnectObjectTree(*it); + it++; + } + + if (haystack.obj) + haystack.obj->disconnect(this); +} + void QDBusConnectionPrivate::closeConnection() { QDBusWriteLocker locker(CloseConnectionAction, this); @@ -1095,6 +1107,18 @@ void QDBusConnectionPrivate::closeConnection() } qDeleteAll(pendingCalls); + + // Disconnect all signals from signal hooks and from the object tree to + // avoid QObject::destroyed being sent to dbus daemon thread which has + // already quit. + SignalHookHash::iterator sit = signalHooks.begin(); + while (sit != signalHooks.end()) { + sit.value().obj->disconnect(this); + sit++; + } + + disconnectObjectTree(rootNode); + rootNode.children.clear(); // free resources } void QDBusConnectionPrivate::checkThread() -- cgit v1.2.3