[PATCH AUTOSEL 4.19 18/74] bpf/tests: Do not PASS tests without actually testing the result

[Sasha Levin]

From: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx>

[ Upstream commit 2b7e9f25e590726cca76700ebdb10e92a7a72ca1 ]

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@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20210721103822.3755111-1-johan.almbladh@xxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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 98074a3bc161..49d79079e8b3 100644
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -6687,7 +6687,14 @@ 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;
 
-- 
2.30.2