Some subtests can be unstable, failing once every X runs. Fixing them can take time: there could be an issue in the kernel or in the subtest, and it is then important to do a proper analysis, not to hide real bugs.

To avoid creating noises on the different CIs, it is important to have a simple way to mark subtests as flaky, and ignore the errors. This is what this patch introduces: subtests can be marked as flaky by setting MPTCP_LIB_SUBTEST_FLAKY env var to 1, e.g.

MPTCP_LIB_SUBTEST_FLAKY=1 <run flaky subtest>

The subtest will be executed, and errors (if any) will be ignored. It is still good to run these subtests, as it exercises code, and the results can still be useful for the on-going investigations.

Note that the MPTCP CI will continue to track these flaky subtests by setting SELFTESTS_MPTCP_LIB_OVERRIDE_FLAKY env var to 1, and a ticket has to be created before marking subtests as flaky.

Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- tools/testing/selftests/net/mptcp/mptcp_lib.sh | 30 ++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh b/tools/testing/selftests/net/mptcp/mptcp_lib.sh index ad2ebda5cb64..6ffa9b7a3260 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh @@ -21,6 +21,7 @@ declare -rx MPTCP_LIB_AF_INET6=10

MPTCP_LIB_SUBTESTS=() MPTCP_LIB_SUBTESTS_DUPLICATED=0 +MPTCP_LIB_SUBTEST_FLAKY=0 MPTCP_LIB_TEST_COUNTER=0 MPTCP_LIB_TEST_FORMAT="%02u %-50s" MPTCP_LIB_IP_MPTCP=0 @@ -41,6 +42,16 @@ else readonly MPTCP_LIB_COLOR_RESET= fi

+# SELFTESTS_MPTCP_LIB_OVERRIDE_FLAKY env var can be set not to ignore errors +# from subtests marked as flaky +mptcp_lib_override_flaky() { + [ "${SELFTESTS_MPTCP_LIB_OVERRIDE_FLAKY:-}" = 1 ] +} + +mptcp_lib_subtest_is_flaky() { + [ "${MPTCP_LIB_SUBTEST_FLAKY}" = 1 ] && ! mptcp_lib_override_flaky +} + # $1: color, $2: text mptcp_lib_print_color() { echo -e "${MPTCP_LIB_START_PRINT:-}${*}${MPTCP_LIB_COLOR_RESET}" @@ -72,7 +83,16 @@ mptcp_lib_pr_skip() { }

mptcp_lib_pr_fail() { - mptcp_lib_print_err "[FAIL]${1:+ ${*}}" + local title cmt + + if mptcp_lib_subtest_is_flaky; then + title="IGNO" + cmt=" (flaky)" + else + title="FAIL" + fi + + mptcp_lib_print_err "[${title}]${cmt}${1:+ ${*}}" }

mptcp_lib_pr_info() { @@ -208,7 +228,13 @@ mptcp_lib_result_pass() {

# $1: test name mptcp_lib_result_fail() { - __mptcp_lib_result_add "not ok" "${1}" + if mptcp_lib_subtest_is_flaky; then + # It might sound better to use 'not ok # TODO' or 'ok # SKIP', + # but some CIs don't understand 'TODO' and treat SKIP as errors. + __mptcp_lib_result_add "ok" "${1} # IGNORE Flaky" + else + __mptcp_lib_result_add "not ok" "${1}" + fi }

# $1: test name

These tests are flaky since their introduction. This might be less or not visible depending on the CI running the tests, especially if it is also busy doing other tasks in parallel, and if a debug kernel config is being used.

It looks like this issue is often present with the NetDev CI. While this is being investigated, the tests are marked as flaky not to create noises on such CIs.

Fixes: 01542c9bf9ab ("selftests: mptcp: add fastclose testcase") Link: https://github.com/multipath-tcp/mptcp_net-next/issues/324 Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- tools/testing/selftests/net/mptcp/mptcp_join.sh | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh index fefa9173bdaa..b869b46823d7 100755 --- a/tools/testing/selftests/net/mptcp/mptcp_join.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh @@ -261,6 +261,8 @@ reset()

TEST_NAME="${1}"

+ MPTCP_LIB_SUBTEST_FLAKY=0 # reset if modified + if skip_test; then MPTCP_LIB_TEST_COUNTER=$((MPTCP_LIB_TEST_COUNTER+1)) last_test_ignored=1 @@ -448,7 +450,9 @@ reset_with_tcp_filter() # $1: err msg fail_test() { - ret=${KSFT_FAIL} + if ! mptcp_lib_subtest_is_flaky; then + ret=${KSFT_FAIL} + fi

if [ ${#} -gt 0 ]; then print_fail "${@}" @@ -3069,6 +3073,7 @@ fullmesh_tests() fastclose_tests() { if reset_check_counter "fastclose test" "MPTcpExtMPFastcloseTx"; then + MPTCP_LIB_SUBTEST_FLAKY=1 test_linkfail=1024 fastclose=client \ run_tests $ns1 $ns2 10.0.1.1 chk_join_nr 0 0 0 @@ -3077,6 +3082,7 @@ fastclose_tests() fi

if reset_check_counter "fastclose server test" "MPTcpExtMPFastcloseRx"; then + MPTCP_LIB_SUBTEST_FLAKY=1 test_linkfail=1024 fastclose=server \ run_tests $ns1 $ns2 10.0.1.1 chk_join_nr 0 0 0 0 0 0 1