kunit.py isn't very clear that 1) it stashes a copy of the unparsed output in $BUILD_DIR/test.log 2) it sets $BUILD_DIR=.kunit by default

So it's trickier than it should be for a user to come up with the right command to do so.

Make kunit.py print out a command for this if a) we saw a test case crash b) we only ran one kernel (test.log only contains output from the last)

Example suggested command: $ scripts/decode_stacktrace.sh .kunit/vmlinux .kunit < .kunit/test.log | tee .kunit/decoded.log | ./tools/testing/kunit/kunit.py parse

Without debug info a user might see something like [14:11:25] Call Trace: [14:11:25] ? kunit_binary_assert_format (:?) [14:11:25] kunit_try_run_case (test.c:?) [14:11:25] ? __kthread_parkme (kthread.c:?) [14:11:25] kunit_generic_run_threadfn_adapter (try-catch.c:?) [14:11:25] ? kunit_generic_run_threadfn_adapter (try-catch.c:?) [14:11:25] kthread (kthread.c:?) [14:11:25] new_thread_handler (:?) [14:11:25] [CRASHED]

`tee` is in GNU coreutils, so it seems fine to add that into the pipeline by default, that way users can inspect the otuput in more detail.

Note: to turn on debug info, users would need to do something like $ echo -e 'CONFIG_DEBUG_KERNEL=y\nCONFIG_DEBUG_INFO=y' >> .kunit/.kunitconfig $ ./tools/testing/kunit/kunit.py config $ ./tools/testing/kunit/kunit.py build $ <then run decode_stacktrace.sh now vmlinux is updated>

This feels too clunky to include in the instructions. With --kconfig_add [1], it would become a bit less painful.

[1] https://lore.kernel.org/linux-kselftest/20211106013058.2621799-2-dlatypov@go...

Signed-off-by: Daniel Latypov dlatypov@google.com --- tools/testing/kunit/kunit.py | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/tools/testing/kunit/kunit.py b/tools/testing/kunit/kunit.py index 68e6f461c758..a45836ac2ca1 100755 --- a/tools/testing/kunit/kunit.py +++ b/tools/testing/kunit/kunit.py @@ -156,6 +156,12 @@ def exec_tests(linux: kunit_kernel.LinuxSourceTree, request: KunitExecRequest,

test_counts.add_subtest_counts(result.result.test.counts)

+ if len(filter_globs) == 1 and test_counts.crashed > 0: + bd = request.build_dir + print('The kernel seems to have crashed; you can decode the stack traces with:') + print('$ scripts/decode_stacktrace.sh {}/vmlinux {} < {} | tee {}/decoded.log | {} parse'.format( + bd, bd, kunit_kernel.get_outfile_path(bd), bd, sys.argv[0])) + kunit_status = _map_to_overall_status(test_counts.get_status()) return KunitResult(status=kunit_status, result=result.result, elapsed_time=exec_time)

base-commit: fa55b7dcdc43c1aa1ba12bca9d2dd4318c2a0dbf