I started development on Debian 5.0.7, and now switched to Ubuntu 10.10. Qt installed 4.7.1.

I'm using Qextserialport and after OS switch I found 100% cpu load. I checked with gprof and found this :

Flat profile:

Each sample counts as 0.01 seconds.
% cumulative self self total
time seconds seconds calls Ts/call Ts/call name
60.00 0.06 0.06 QextSerialPort::qt_metacall(QMetaObject::Call, int, void**)
40.00 0.10 0.04 QextSerialPort::qt_metacast(char const*)
0.00 0.10 0.00 8642 0.00 0.00 QByteArray::size() const
0.00 0.10 0.00 4850 0.00 0.00 qt_noop()
0.00 0.10 0.00 4502 0.00 0.00 QByteArray::at(int) const
0.00 0.10 0.00 1069 0.00 0.00 QBasicAtomicInt::deref()
0.00 0.10 0.00 885 0.00 0.00 QString::~QString()
Where to look and how to track the problem ?