Application hangs in QDashStroker::processCurrentSubpath

My application hangs unreproducibly in QDashStroker::processCurrentSubpath

I managed to capture a stacktrace and stepped through the code to dump the pattern of lines that are repeated in the code. See attachments.

The particular backtrace was captured on a Fedora 21 system, however, I experienced similar hangs (without the possibility to debug them) on an Ubuntu 12.04 machine (with Qt 5.4 installed).

Edit:
As described below, I've narrowed down the problem: Drawing a Qt::DashLine with 1.5 width to a point with an "Infinity" in its coordinates causes the hang. See qt-qstroker-bug.tar.bz2 for a MWE.