On Wed, Jul 27, 2022 at 06:29:55PM +0000, Daniel Müller wrote:
> The send_signal/send_signal_tracepoint is pretty flaky, with at least
> one failure in every ten runs on a few attempts I've tried it:
> > test_send_signal_common:PASS:pipe_c2p 0 nsec
> > test_send_signal_common:PASS:pipe_p2c 0 nsec
> > test_send_signal_common:PASS:fork 0 nsec
> > test_send_signal_common:PASS:skel_open_and_load 0 nsec
> > test_send_signal_common:PASS:skel_attach 0 nsec
> > test_send_signal_common:PASS:pipe_read 0 nsec
> > test_send_signal_common:PASS:pipe_write 0 nsec
> > test_send_signal_common:PASS:reading pipe 0 nsec
> > test_send_signal_common:PASS:reading pipe error: size 0 0 nsec
> > test_send_signal_common:FAIL:incorrect result unexpected incorrect result: actual 48 != expected 50
> > test_send_signal_common:PASS:pipe_write 0 nsec
> > #139/1 send_signal/send_signal_tracepoint:FAIL
>
> The reason does not appear to be a correctness issue in the strict
> sense. Rather, we merely do not receive the signal we are waiting for
> within the provided timeout.
> Let's bump the timeout by a factor of ten. With that change I have not
> been able to reproduce the failure in 150+ iterations. I am also sneaking
> in a small simplification to the test_progs test selection logic.
>
> Signed-off-by: Daniel Müller <deso@xxxxxxxxxx>
I reproduced the fail, can't reproduce anymore with the fix
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
jirka
> ---
> tools/testing/selftests/bpf/prog_tests/send_signal.c | 2 +-
> tools/testing/selftests/bpf/test_progs.c | 7 ++-----
> 2 files changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/send_signal.c b/tools/testing/selftests/bpf/prog_tests/send_signal.c
> index d71226e..d63a20 100644
> --- a/tools/testing/selftests/bpf/prog_tests/send_signal.c
> +++ b/tools/testing/selftests/bpf/prog_tests/send_signal.c
> @@ -64,7 +64,7 @@ static void test_send_signal_common(struct perf_event_attr *attr,
> ASSERT_EQ(read(pipe_p2c[0], buf, 1), 1, "pipe_read");
>
> /* wait a little for signal handler */
> - for (int i = 0; i < 100000000 && !sigusr1_received; i++)
> + for (int i = 0; i < 1000000000 && !sigusr1_received; i++)
> j /= i + j + 1;
>
> buf[0] = sigusr1_received ? '2' : '0';
> diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
> index c639f2e..3561c9 100644
> --- a/tools/testing/selftests/bpf/test_progs.c
> +++ b/tools/testing/selftests/bpf/test_progs.c
> @@ -1604,11 +1604,8 @@ int main(int argc, char **argv)
> struct prog_test_def *test = &prog_test_defs[i];
>
> test->test_num = i + 1;
> - if (should_run(&env.test_selector,
> - test->test_num, test->test_name))
> - test->should_run = true;
> - else
> - test->should_run = false;
> + test->should_run = should_run(&env.test_selector,
> + test->test_num, test->test_name);
>
> if ((test->run_test == NULL && test->run_serial_test == NULL) ||
> (test->run_test != NULL && test->run_serial_test != NULL)) {
> --
> 2.30.2
>
