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From b024fbe83863fc57364a52c717d5b43d654bdb5d Mon Sep 17 00:00:00 2001
From: Weng Xuetian <wengxt@gmail.com>
Date: Sat, 5 Mar 2016 12:23:21 -0800
Subject: [PATCH] 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
---
src/dbus/qdbusconnection_p.h | 1 +
src/dbus/qdbusintegrator.cpp | 28 +++++++++++++++++++++++++++-
2 files changed, 28 insertions(+), 1 deletion(-)
diff --git a/src/dbus/qdbusconnection_p.h b/src/dbus/qdbusconnection_p.h
index c77daf7..565eb83 100644
--- a/src/dbus/qdbusconnection_p.h
+++ b/src/dbus/qdbusconnection_p.h
@@ -254,6 +254,7 @@ private:
const QVector<int> &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 cd44861..a3cd47b 100644
--- a/src/dbus/qdbusintegrator.cpp
+++ b/src/dbus/qdbusintegrator.cpp
@@ -1030,7 +1030,6 @@ QDBusConnectionPrivate::~QDBusConnectionPrivate()
qPrintable(name));
closeConnection();
- rootNode.children.clear(); // free resources
qDeleteAll(cachedMetaObjects);
if (mode == ClientMode || mode == PeerMode) {
@@ -1052,6 +1051,20 @@ 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);
@@ -1075,6 +1088,19 @@ void QDBusConnectionPrivate::closeConnection()
}
qDeleteAll(pendingCalls);
+
+ // clean up all signal hook and object tree, to avoid QObject::destroyed
+ // being activated to dbus daemon thread which already quits.
+ // dbus connection is already closed, so there is nothing we could do be clean
+ // up everything here.
+ 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()
--
2.7.1
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