On Wed 2020-06-10 13:20:59, Joe Lawrence wrote:
> Inspired by commit f131d9edc29d ("selftests/lkdtm: Don't clear dmesg
> when running tests"), keep a reference dmesg copy when beginning each
> test. This way check_result() can compare against the initial copy
> rather than relying upon an empty log.
>
> Signed-off-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
> ---
> tools/testing/selftests/livepatch/README | 16 +++---
> .../testing/selftests/livepatch/functions.sh | 16 +++++-
> .../selftests/livepatch/test-callbacks.sh | 55 ++++---------------
> .../selftests/livepatch/test-ftrace.sh | 5 +-
> .../selftests/livepatch/test-livepatch.sh | 15 +----
> .../selftests/livepatch/test-shadow-vars.sh | 5 +-
> .../testing/selftests/livepatch/test-state.sh | 20 ++-----
> 7 files changed, 43 insertions(+), 89 deletions(-)
>
> diff --git a/tools/testing/selftests/livepatch/README b/tools/testing/selftests/livepatch/README
> index 621d325425c2..0942dd5826f8 100644
> --- a/tools/testing/selftests/livepatch/README
> +++ b/tools/testing/selftests/livepatch/README
> @@ -6,8 +6,8 @@ This is a small set of sanity tests for the kernel livepatching.
>
> The test suite loads and unloads several test kernel modules to verify
> livepatch behavior. Debug information is logged to the kernel's message
> -buffer and parsed for expected messages. (Note: the tests will clear
> -the message buffer between individual tests.)
> +buffer and parsed for expected messages. (Note: the tests will compare
> +the message buffer for only the duration of each individual test.)
>
>
> Config
> @@ -35,9 +35,9 @@ Adding tests
> ------------
>
> See the common functions.sh file for the existing collection of utility
> -functions, most importantly setup_config() and check_result(). The
> -latter function greps the kernel's ring buffer for "livepatch:" and
> -"test_klp" strings, so tests be sure to include one of those strings for
> -result comparison. Other utility functions include general module
> -loading and livepatch loading helpers (waiting for patch transitions,
> -sysfs entries, etc.)
> +functions, most importantly setup_config(), start_test() and
> +check_result(). The latter function greps the kernel's ring buffer for
> +"livepatch:" and "test_klp" strings, so tests be sure to include one of
> +those strings for result comparison. Other utility functions include
> +general module loading and livepatch loading helpers (waiting for patch
> +transitions, sysfs entries, etc.)
> diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh
> index 2aab9791791d..e84375a33852 100644
> --- a/tools/testing/selftests/livepatch/functions.sh
> +++ b/tools/testing/selftests/livepatch/functions.sh
> @@ -243,13 +243,25 @@ function set_pre_patch_ret {
> die "failed to set pre_patch_ret parameter for $mod module"
> }
>
> +function start_test {
> + local test="$1"
> +
> + # Save existing dmesg so we can detect new content below
> + SAVED_DMESG=$(mktemp --tmpdir -t klp-dmesg-XXXXXX)
There is a nice trick how to remove the temporary files even
when the script fails from other reasons. The following should
do the job:
function cleanup {
rm -f "$SAVED_DMESG"
}
trap cleanup EXIT
> + dmesg > "$SAVED_DMESG"
> +
> + echo -n "TEST: $test ... "
> +}
> +
> # check_result() - verify dmesg output
> # TODO - better filter, out of order msgs, etc?
> function check_result {
> local expect="$*"
> local result
>
> - result=$(dmesg | grep -v 'tainting' | grep -e 'livepatch:' -e 'test_klp' | sed 's/^\[[ 0-9.]*\] //')
> + result=$(dmesg | diff --changed-group-format='%>' --unchanged-group-format='' "$SAVED_DMESG" - | \
> + grep -v 'tainting' | grep -e 'livepatch:' -e 'test_klp' | \
> + sed 's/^\[[ 0-9.]*\] //')
>
> if [[ "$expect" == "$result" ]] ; then
> echo "ok"
> @@ -257,4 +269,6 @@ function check_result {
> echo -e "not ok\n\n$(diff -upr --label expected --label result <(echo "$expect") <(echo "$result"))\n"
> die "livepatch kselftest(s) failed"
> fi
> +
> + rm -f "$SAVED_DMESG"
This change will not be necessary with the above trap handler.
Otherwise, I really like the change. I was always a bit worried that these
tests were clearing all other messages.
Best Regards,
Petr
