Memory leak in my threaded SSL server application

[moosa]

Yes, I printed a qDebug message on the MessageThread destructor when it is deleted and saw that the destructor is being called.

[TMan]

And the QTcpSocket/QSslSocket you create in MessageThread, are those deleted? Also, have you tried running with valgrind?

[moosa]

I am getting into the valgrind tool right now.

About the QSslSocket, yes I am deleting it.
One thing that decreased the memory leak noticeably (but not at all) is moving the following code from the "performCleanExit" function in the thread:

m_socket->deleteLater();
m_authTimer->deleteLater();

m_socket->deleteLater();
m_authTimer->deleteLater();

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to the following code in thread destructor:

delete m_socket;
delete m_authTimer;

delete m_socket;
delete m_authTimer;

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It may be related to that that the deleteLater() function does not enter the event loop (in order to be executed) before the thread is deleted.

I will make further investigation and try to provide the client code as well in order to be able to reproduce the memory leak easily.

Thanks in advance

[sadjoker]

Hello, i`ll watch that thread closely for your final investigation about the memory leak. I`ve got the same problem with a multithreaded QSslSocket app myself and the memory of my server app goes up like ~700kb per client connect/disconnect. And my code is similar to yours.

[moosa]

By the way, I am using QT version 4.6.2.

There is a reported bug about QSslSocket memory leak in the following link: http://bugreports.qt.nokia.com/browse/QTBUG-6504
I do not know whether or not this the problem I am having here.

Regards

[moosa]

Finally I found the code causing the memory leak:
In the server side, setting the private key causes a memory leak. It seems like a bug in QT.

The code that causes the memory leak is:

m_socket->setPrivateKey(":/certs/my-key.pem");  //  Add the key that will make the handshake
m_socket->setLocalCertificate(":/certs/my-cert.pem");

m_socket->setPrivateKey(":/certs/my-key.pem");  //  Add the key that will make the handshake
m_socket->setLocalCertificate(":/certs/my-cert.pem");

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[moosa]

I think this is the bug reported:
http://bugreports.qt.nokia.com/browse/QTBUG-6504