Program received signal SIGSEGV, Segmentation fault.
0x00007ffff4901898 in QgsCoordinateTransform::transform (this=0x0, thePoint=..., 
    direction=QgsCoordinateTransform::ReverseTransform)
    at /home/sam/pacchetti_gis/Quantum-GIS/src/core/qgscoordinatetransform.cpp:228
228	  if ( mShortCircuit || !mInitialisedFlag )
(gdb) bt full
#0  0x00007ffff4901898 in QgsCoordinateTransform::transform (this=0x0, thePoint=..., 
    direction=QgsCoordinateTransform::ReverseTransform)
    at /home/sam/pacchetti_gis/Quantum-GIS/src/core/qgscoordinatetransform.cpp:228
        x = 6.9533558070073456e-310
        y = 9.3676111259553698e-317
        z = 0
        __FUNCTION__ = "transform"
#1  0x00007ffff49adaf4 in QgsMapRenderer::mapToLayerCoordinates (this=0x1214f80, theLayer=0x0, 
    point=...) at /home/sam/pacchetti_gis/Quantum-GIS/src/core/qgsmaprenderer.cpp:950
No locals.
#2  0x00007ffff422d087 in QgsMapTool::toLayerCoordinates (this=0x12d3b30, layer=0x0, point=...)
    at /home/sam/pacchetti_gis/Quantum-GIS/src/gui/qgsmaptool.cpp:50
No locals.
#3  0x00007ffff422cffe in QgsMapTool::toLayerCoordinates (this=0x12d3b30, layer=0x0, point=...)
    at /home/sam/pacchetti_gis/Quantum-GIS/src/gui/qgsmaptool.cpp:45
        pt = {m_x = 624091.69285712962, m_y = 4344776.650152918}
#4  0x00000000006ff20d in QgsMapToolNodeTool::canvasPressEvent (this=0x12d3b30, e=0x7fffffffcb50)
    at /home/sam/pacchetti_gis/Quantum-GIS/src/app/nodetool/qgsmaptoolnodetool.cpp:373
        tol = 1.1363509854348671e-322
        dist = 4.5676991480737003e-317
        closestLayerVertex = {m_x = 6.9533454565581496e-310, m_y = 8.2768485657935663e-317}
        layerCoordPoint = {m_x = 0, m_y = 8.2768485657935663e-317}
        atVertex = 32767
---Type <return> to continue, or q <return> to quit---
        beforeVertex = -15824
        afterVertex = 0
        _qgsScopeLogger = {_file = 
    0x97e648 "/home/sam/pacchetti_gis/Quantum-GIS/src/app/nodetool/qgsmaptoolnodetool.cpp", 
          _func = 0x97e890 "canvasPressEvent", _line = 348}
        __FUNCTION__ = "canvasPressEvent"
        vlayer = 0x0
        snapResults = {{p = {static shared_null = {ref = {_q_value = 7378}, alloc = 0, begin = 0, 
                end = 0, sharable = 1, array = {0x0}}, d = 0xe056a0}, d = 0xe056a0}}
#5  0x00007ffff4221e09 in QgsMapCanvas::mousePressEvent (this=0x116b140, e=0x7fffffffcb50)
    at /home/sam/pacchetti_gis/Quantum-GIS/src/gui/qgsmapcanvas.cpp:961
No locals.
#6  0x00007ffff28da2b3 in QWidget::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
No symbol table info available.
#7  0x00007ffff2c84d36 in QFrame::event(QEvent*) () from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
No symbol table info available.
#8  0x00007ffff2e9d37b in QGraphicsView::viewportEvent(QEvent*) ()
   from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
No symbol table info available.
#9  0x00007ffff34e0cc6 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*)
    () from /usr/lib/x86_64-linux-gnu/libQtCore.so.4
No symbol table info available.
#10 0x00007ffff288a6dc in QApplicationPrivate::notify_helper(QObject*, QEvent*) ()
---Type <return> to continue, or q <return> to quit---
   from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
No symbol table info available.
#11 0x00007ffff288f3eb in QApplication::notify(QObject*, QEvent*) ()
   from /usr/lib/x86_64-linux-gnu/libQtGui.so.4
No symbol table info available.
#12 0x00007ffff48eb120 in QgsApplication::notify (this=0x7fffffffd890, receiver=0xff7a10, event=
    0x7fffffffcb50) at /home/sam/pacchetti_gis/Quantum-GIS/src/core/qgsapplication.cpp:242
        done = true