On 7/27/22 11:29 AM, 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>
Okay, this test has been improved *multiple* times to address its
flakiness. We tried very hard not to increase the runtime for it
so we don't increase overall test_progs run time. But looks like
we have to do it to make it robust. Hopefully such a 10x number
of iterations can finally address the flakiness issue.
Acked-by: Yonghong Song <yhs@xxxxxx>
---
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)) {
