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KASAN: Testing Documentation

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Include documentation on how to test KASAN using CONFIG_TEST_KASAN_KUNIT
and CONFIG_TEST_KASAN_MODULE.

Signed-off-by: Patricia Alfonso <trishalfonso@google.com>
Signed-off-by: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Brendan Higgins <brendanhiggins@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20200915035828.570483-5-davidgow@google.com
Link: https://lkml.kernel.org/r/20200910070331.3358048-5-davidgow@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Patricia Alfonso 2020-10-13 16:55:09 -07:00 committed by Linus Torvalds
parent 73228c7ecc
commit 9ab5be9768
1 changed files with 70 additions and 0 deletions
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Documentation/dev-tools/kasan.rst
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@ -281,3 +281,73 @@ unmapped. This will require changes in arch-specific code.
This allows ``VMAP_STACK`` support on x86, and can simplify support of
architectures that do not have a fixed module region.
CONFIG_KASAN_KUNIT_TEST & CONFIG_TEST_KASAN_MODULE
--------------------------------------------------
``CONFIG_KASAN_KUNIT_TEST`` utilizes the KUnit Test Framework for testing.
This means each test focuses on a small unit of functionality and
there are a few ways these tests can be run.
Each test will print the KASAN report if an error is detected and then
print the number of the test and the status of the test:
pass::
ok 28 - kmalloc_double_kzfree
or, if kmalloc failed::
# kmalloc_large_oob_right: ASSERTION FAILED at lib/test_kasan.c:163
Expected ptr is not null, but is
not ok 4 - kmalloc_large_oob_right
or, if a KASAN report was expected, but not found::
# kmalloc_double_kzfree: EXPECTATION FAILED at lib/test_kasan.c:629
Expected kasan_data->report_expected == kasan_data->report_found, but
kasan_data->report_expected == 1
kasan_data->report_found == 0
not ok 28 - kmalloc_double_kzfree
All test statuses are tracked as they run and an overall status will
be printed at the end::
ok 1 - kasan
or::
not ok 1 - kasan
(1) Loadable Module
~~~~~~~~~~~~~~~~~~~~
With ``CONFIG_KUNIT`` enabled, ``CONFIG_KASAN_KUNIT_TEST`` can be built as
a loadable module and run on any architecture that supports KASAN
using something like insmod or modprobe. The module is called ``test_kasan``.
(2) Built-In
~~~~~~~~~~~~~
With ``CONFIG_KUNIT`` built-in, ``CONFIG_KASAN_KUNIT_TEST`` can be built-in
on any architecure that supports KASAN. These and any other KUnit
tests enabled will run and print the results at boot as a late-init
call.
(3) Using kunit_tool
~~~~~~~~~~~~~~~~~~~~~
With ``CONFIG_KUNIT`` and ``CONFIG_KASAN_KUNIT_TEST`` built-in, we can also
use kunit_tool to see the results of these along with other KUnit
tests in a more readable way. This will not print the KASAN reports
of tests that passed. Use `KUnit documentation <https://www.kernel.org/doc/html/latest/dev-tools/kunit/index.html>`_ for more up-to-date
information on kunit_tool.
.. _KUnit: https://www.kernel.org/doc/html/latest/dev-tools/kunit/index.html
``CONFIG_TEST_KASAN_MODULE`` is a set of KASAN tests that could not be
converted to KUnit. These tests can be run only as a module with
``CONFIG_TEST_KASAN_MODULE`` built as a loadable module and
``CONFIG_KASAN`` built-in. The type of error expected and the
function being run is printed before the expression expected to give
an error. Then the error is printed, if found, and that test
should be interpretted to pass only if the error was the one expected
by the test.