bpf/tests: Do not PASS tests without actually testing the result

Each test case can have a set of sub-tests, where each sub-test can
run the cBPF/eBPF test snippet with its own data_size and expected
result. Before, the end of the sub-test array was indicated by both
data_size and result being zero. However, most or all of the internal
eBPF tests has a data_size of zero already. When such a test also had
an expected value of zero, the test was never run but reported as
PASS anyway.

Now the test runner always runs the first sub-test, regardless of the
data_size and result values. The sub-test array zero-termination only
applies for any additional sub-tests.

There are other ways fix it of course, but this solution at least
removes the surprise of eBPF tests with a zero result always succeeding.

Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210721103822.3755111-1-johan.almbladh@anyfinetworks.com

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 1c5299cb3f19979a7594c2687331560f8129b37e..f6d5d30d01bf2e4caf420dac029a474b520aeb7c 100644 (file)
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -6659,7 +6659,14 @@ static int run_one(const struct bpf_prog *fp, struct bpf_test *test)
                u64 duration;
                u32 ret;
 
-               if (test->test[i].data_size == 0 &&
+               /*
+                * NOTE: Several sub-tests may be present, in which case
+                * a zero {data_size, result} tuple indicates the end of
+                * the sub-test array. The first test is always run,
+                * even if both data_size and result happen to be zero.
+                */
+               if (i > 0 &&
+                   test->test[i].data_size == 0 &&
                    test->test[i].result == 0)
                        break;