VERSION: 2014 (and possibly earlier)
PROBLEM:
Using the Linework tool causes Revit to crash.
Usually in sections, elevation or 3D views.
POSSIBLE CAUSE:
There is a linked Revit file created from an IFC file visible in the view.
(Prior to 2014 the only way to bring an IFC file in was to open it in Revit, save it as a Revit file, then link the Revit file into your project).
Revit 2015 hasn't been tested for this bug.
SOLUTION:
Turn off the linked file in the view, use Visibility/Graphics to either untick the link itself, or the workset the link is on.
Use the Linework tool, then turn the link back on.
Alternatively if the linked file is no longer needed remove it from the project.
HOW TO AVOID:
Turn off IFC links before using the Linework tool in sections, elevation and 3D views.