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authorPatricia Alfonso <trishalfonso@google.com>2020-10-14 02:55:09 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-14 04:38:32 +0300
commit9ab5be976898860f70f67257be725b891ded10ea (patch)
tree1c2b96e0ee835c2f31ecc428a2f99e0dd4cb7b46 /Documentation/dev-tools/kasan.rst
parent73228c7ecc5e40c0851c4703c5ec6ed38123e989 (diff)
downloadlinux-9ab5be976898860f70f67257be725b891ded10ea.tar.xz
KASAN: Testing Documentation
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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@@ -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.