On Mar 28, 2021, at 4:26 AM, Jiri Olsa [off-list ref] wrote:

Adding the test to re-attach (detach/attach again) tracing
fentry programs, plus check that already linked program can't
be attached again.

Fixing the number of check-ed results, which should be 8.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>

[...]

+
+void test_fentry_test(void)
+{
+	struct fentry_test *fentry_skel = NULL;
+	struct bpf_link *link;
+	int err;
+
+	fentry_skel = fentry_test__open_and_load();
+	if (CHECK(!fentry_skel, "fentry_skel_load", "fentry skeleton failed\n"))
+		goto cleanup;
+
+	err = fentry_test__attach(fentry_skel);
+	if (CHECK(err, "fentry_attach", "fentry attach failed: %d\n", err))
+		goto cleanup;
+
+	err = fentry_test(fentry_skel);
+	if (CHECK(err, "fentry_test", "fentry test failed: %d\n", err))
+		goto cleanup;
+
+	fentry_test__detach(fentry_skel);
+
+	/* Re-attach and test again */
+	err = fentry_test__attach(fentry_skel);
+	if (CHECK(err, "fentry_attach", "fentry re-attach failed: %d\n", err))
+		goto cleanup;
+
+	link = bpf_program__attach(fentry_skel->progs.test1);
+	if (CHECK(!IS_ERR(link), "attach_fentry re-attach without detach",
+		  "err: %ld\n", PTR_ERR(link)))

nit: I guess we shouldn't print PTR_ERR(link) when link is not an error code?
This shouldn't break though. 

Thanks,
Song

+		goto cleanup;
+
+	err = fentry_test(fentry_skel);
+	CHECK(err, "fentry_test", "fentry test failed: %d\n", err);
+
cleanup:
	fentry_test__destroy(fentry_skel);
}
-- 
2.30.2