[PATCH] 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>
---
 lib/test_bpf.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index d500320778c7..baff847a02da 100644
--- 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;
 

-- 
2.25.1

On Wed, Jul 21, 2021 at 3:39 AM Johan Almbladh
[off-list ref] wrote:

This feels pretty arbitrary, of course, but I don't see how to improve
this easily without tons of code churn for each test specification.
Applied to bpf-next, thanks!

+                   test->test[i].data_size == 0 &&
                    test->test[i].result == 0)
                        break;

--
2.25.1

Hello:

This patch was applied to bpf/bpf-next.git (refs/heads/master):

On Wed, 21 Jul 2021 12:38:22 +0200 you wrote:

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.

[...]

Here is the summary with links:
  - bpf/tests: do not PASS tests without actually testing the result
    https://git.kernel.org/bpf/bpf-next/c/2b7e9f25e590

You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html