From: Jonathan Bastari Thamrin <[email protected]> wq test fails with ok_sleepable reading 0 instead of 2 as workqueue callback hasn't executed before check.
This happens as callback runs later on a kworker and 50us isn't always enough. Change from 50us sleep to polling over 1s. Before (usleep(50)): 3 fails out of 5000 runs Diagnosing issue (usleep(0)): 23 out of 100 runs After (Polling): 0 out of 5000 runs Tested using vmtest on x86_64, test pinned to one CPU with `yes` load Link: https://github.com/kernel-patches/vmtest/issues/455 Signed-off-by: Jonathan Bastari Thamrin <[email protected]> --- tools/testing/selftests/bpf/prog_tests/wq.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/wq.c b/tools/testing/selftests/bpf/prog_tests/wq.c index 84831eecc..b55d8547f 100644 --- a/tools/testing/selftests/bpf/prog_tests/wq.c +++ b/tools/testing/selftests/bpf/prog_tests/wq.c @@ -7,7 +7,7 @@ void serial_test_wq(void) { struct wq *wq_skel = NULL; - int err, prog_fd; + int err, prog_fd, tries; LIBBPF_OPTS(bpf_test_run_opts, topts); @@ -28,7 +28,13 @@ void serial_test_wq(void) ASSERT_OK(err, "test_run"); ASSERT_EQ(topts.retval, 0, "test_run"); - usleep(50); /* 10 usecs should be enough, but give it extra */ + /* loop check over 1 sec to make sure it doesn't fail early when busy */ + for (tries = 1000; tries >= 0; tries--) { + if (wq_skel->bss->ok_sleepable == (1 << 1)) + break; + + usleep(1000); + } ASSERT_EQ(wq_skel->bss->ok_sleepable, (1 << 1), "ok_sleepable"); clean_up: --- base-commit: b5a4aa31abd6fe90009b63e35dc18c67d041ec0c change-id: 20261005-wq-poll-fix-f46c47dbaf03 Best regards, -- Jonathan Bastari Thamrin <[email protected]>
