[Quickfix-developers] Bug #53 - Possible deadlock if sendToTarget is called in Java fromApp() callbacks

[Joerg T. <Joe...@ma...>]

Hi all,

in some rare situations Java application using QuickFIX may deadlock rendering the FIX 
connection dead:

http://www.quickfixengine.org/bugtracker/bug.php?op=show&bugid=53

All Java objects implementing the Application interface are protected by a C++ level mutex.

In some rare situations, two thread may lock the mutex of the C++ Session object and the 
JavaApplication mutex in different order, causing a deadlock.

Typical scenario:

Thread 1: started by QuickFIX, locks JavaApplication.m_mutex in fromApp(), locks 
Session.m_mutex in sendToTarget()

Thread 2: started by Java application, locks Session.m_mutex in sendToTarget(), locks 
JavaApplication.m_mutex in toApp()

Then the thread processing incoming FIX message is deadlocked.

This is fixed in the CVS repository:

http://cvs.sourceforge.net/viewcvs.py/quickfix/quickfix/src/java/JavaApplication.cpp?r1=1.16&r2=1.17
http://cvs.sourceforge.net/viewcvs.py/quickfix/quickfix/src/java/JavaApplication.h?r1=1.11&r2=1.12

You may also patch the current 1.9.4 with these two files.

Cheers, Jörg

-- 
Joerg Thoennes
                                http://macd.com
Tel.: +49 (0)241 44597-24      Macdonald Associates GmbH
Fax : +49 (0)241 44597-10      Lothringer Str. 52, D-52070 Aachen