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Linux Kernel Selftests

The kernel contains a set of "self tests" under the tools/testing/selftests/
directory. These are intended to be small tests to exercise individual code
paths in the kernel. Tests are intended to be run after building, installing
and booting a kernel.

On some systems, hot-plug tests could hang forever waiting for cpu and
memory to be ready to be offlined. A special hot-plug target is created
to run full range of hot-plug tests. In default mode, hot-plug tests run
in safe mode with a limited scope. In limited mode, cpu-hotplug test is
run on a single cpu as opposed to all hotplug capable cpus, and memory
hotplug test is run on 2% of hotplug capable memory instead of 10%.

Running the selftests (hotplug tests are run in limited mode)

To build the tests:
  $ make -C tools/testing/selftests

To run the tests:
  $ make -C tools/testing/selftests run_tests

To build and run the tests with a single command, use:
  $ make kselftest

- note that some tests will require root privileges.

Running a subset of selftests
You can use the "TARGETS" variable on the make command line to specify
single test to run, or a list of tests to run.

To run only tests targeted for a single subsystem:
  $  make -C tools/testing/selftests TARGETS=ptrace run_tests

You can specify multiple tests to build and run:
  $  make TARGETS="size timers" kselftest

See the top-level tools/testing/selftests/Makefile for the list of all
possible targets.

Running the full range hotplug selftests

To build the hotplug tests:
  $ make -C tools/testing/selftests hotplug

To run the hotplug tests:
  $ make -C tools/testing/selftests run_hotplug

- note that some tests will require root privileges.

Install selftests

You can use tool installs selftests in default
location which is tools/testing/selftests/kselftest or a user specified

To install selftests in default location:
   $ cd tools/testing/selftests
   $ ./

To install selftests in a user specified location:
   $ cd tools/testing/selftests
   $ ./ install_dir

Running installed selftests

Kselftest install as well as the Kselftest tarball provide a script
named "" to run the tests.

You can simply do the following to run the installed Kselftests. Please
note some tests will require root privileges.

cd kselftest

Contributing new tests

In general, the rules for selftests are

 * Do as much as you can if you're not root;

 * Don't take too long;

 * Don't break the build on any architecture, and

 * Don't cause the top-level "make run_tests" to fail if your feature is

Contributing new tests(details)

 * Use TEST_GEN_XXX if such binaries or files are generated during
   TEST_PROGS, TEST_GEN_PROGS mean it is the excutable tested by
   executable which is not tested by default.
   TEST_FILES, TEST_GEN_FILES mean it is the file which is used by