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Documentation: kunit: drop obsolete note about uml_abort for coverage
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Commit b6d5799 ("kunit: Add 'kunit_shutdown' option") changes KUnit
to call kernel_halt() by default when done testing.

This fixes the issue with not having .gcda files due to not calling
atexit() handlers, and therefore we can stop recommending people
manually tweak UML code.

The need to use older versions of GCC (<=6) remains however, due to
linktime issues, same as before. Note: There also might still be issues
with .gcda files as well in newer versions.

Signed-off-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
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Daniel Latypov authored and Shuah Khan committed Jul 12, 2021
1 parent ed01ad3 commit a72fa63
Showing 1 changed file with 1 addition and 13 deletions.
14 changes: 1 addition & 13 deletions Documentation/dev-tools/kunit/running_tips.rst
Original file line number Diff line number Diff line change
Expand Up @@ -86,19 +86,7 @@ Generating code coverage reports under UML
.. note::
TODO(brendanhiggins@google.com): There are various issues with UML and
versions of gcc 7 and up. You're likely to run into missing ``.gcda``
files or compile errors. We know one `faulty GCC commit
<https://github.com/gcc-mirror/gcc/commit/8c9434c2f9358b8b8bad2c1990edf10a21645f9d>`_
but not how we'd go about getting this fixed. The compile errors still
need some investigation.

.. note::
TODO(brendanhiggins@google.com): for recent versions of Linux
(5.10-5.12, maybe earlier), there's a bug with gcov counters not being
flushed in UML. This translates to very low (<1%) reported coverage. This is
related to the above issue and can be worked around by replacing the
one call to ``uml_abort()`` (it's in ``os_dump_core()``) with a plain
``exit()``.

files or compile errors.

This is different from the "normal" way of getting coverage information that is
documented in Documentation/dev-tools/gcov.rst.
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