Here is a core dump of when it happens: http://pastebin.com/bs7An14L
It happens on this line of code: CascadeClassifier faceDetector = new CascadeClassifier("/usr/local/share/OpenCV/haarcascades/haarcascade_frontalface_alt.xml");
It used to work fine, it started to happen after upgrade of packages on my distrib I think. I believe it might be due to a native library. I rebuilt OpenCV but no luck. I also tried with OpenCV 3.0 and 3.1.
Any help will be much appreciated :-)