The tarball on http://userweb.kernel.org/~acme/dwarves contains ostra,
a python script to generate callgraph information based on ctracer
collected data.

ostra, as of dwarves version 1.3, is released under the Open Software
License version 1.1, which does not comply with the DFSG. ostra was
therefore removed from the dwarves tarball. See the get-orig.sh script
to see how it's done.