kunit_tool How-To

What is kunit_tool?

kunit_tool is a script (tools/testing/kunit/kunit.py) that aids in building the Linux kernel as UML (User Mode Linux), running KUnit tests, parsing the test results and displaying them in a user friendly manner.

What is a kunitconfig?

It's just a defconfig that kunit_tool looks for in the base directory. kunit_tool uses it to generate a .config as you might expect. In addition, it verifies that the generated .config contains the CONFIG options in the kunitconfig; the reason it does this is so that it is easy to be sure that a CONFIG that enables a test actually ends up in the .config.

How do I use kunit_tool?

If a kunitconfig is present at the root directory, all you have to do is:

./tools/testing/kunit/kunit.py run

However, you most likely want to use it with the following options:

./tools/testing/kunit/kunit.py run --timeout=30 --jobs=`nproc --all`
  • --timeout sets a maximum amount of time to allow tests to run.
  • --jobs sets the number of threads to use to build the kernel.

If you just want to use the defconfig that ships with the kernel, you can append the --defconfig flag as well:

./tools/testing/kunit/kunit.py run --timeout=30 --jobs=`nproc --all` --defconfig


This command is particularly helpful for getting started because it just works. No kunitconfig needs to be present.

For a list of all the flags supported by kunit_tool, you can run:

./tools/testing/kunit/kunit.py run --help