QSystemStorageInfo.availableDiskSpace() not working in Simulator & Windows, crashing on Symbian in thread

The relevant code that is executed on various platforms and both from the main thread and an extra thread:

QSystemStorageInfo info;
qlonglong size = info.availableDiskSpace("c");
qDebug() << "free:" << size;

Simulator:
error at runtime:
Object::connect: No such signal QSystemStorageInfoPrivate::logicalDriveChanged(bool,const QString &) in qsystemstorageinfo.cpp:87

Symbian device:
Works as expected if executed from the main thread. When executing the call from another thread - crash:
Process 1694, thread 1697 stopped at 0x8043e445: Thread 0x6a1 has panicked. Category: KERN-EXEC; Reason: 0
(This panic is raised when the Kernel cannot find an object in the object index for the current process or current thread using the specified object index number (the raw handle number). )

On Windows, QSystemStorageInfo is unfortunately not present, as also mentioned in a comment in the closed issue http://bugreports.qt.nokia.com/browse/QTBUG-14245

Attached a sample to reproduce, with two buttons in the main UI. One calls the code segment above in the main thread, the second button creates a thread (task.cpp) and calls the code from there.