Comment 2 for bug 1156442

StacktraceTop:
 gtk_css_image_linear_transition (start_image=0x2ec4060, end_image=0x2b34780, property_id=43, progress=0.00284450644538494) at /build/buildd/gtk+3.0-3.6.4/./gtk/gtkcssimagelinear.c:481
 gtk_css_value_image_transition (start=0x2ed5ce0, end=<optimized out>, property_id=43, progress=<optimized out>) at /build/buildd/gtk+3.0-3.6.4/./gtk/gtkcssimagevalue.c:77
 gtk_css_value_array_transition_extend (start=0x2b37f80, end=0x2b36220, property_id=43, progress=0.00284450644538494) at /build/buildd/gtk+3.0-3.6.4/./gtk/gtkcssarrayvalue.c:172
 gtk_css_transition_set_values (animation=0x311c780, for_time_us=<optimized out>, values=0x311dcc0) at /build/buildd/gtk+3.0-3.6.4/./gtk/gtkcsstransition.c:46
 _gtk_css_computed_values_advance (values=0x311dcc0, timestamp=timestamp@entry=579281444) at /build/buildd/gtk+3.0-3.6.4/./gtk/gtkcsscomputedvalues.c:546