[PATCH v2 3/3] selftests/hid: prepare test_rdesc_fixup_get_data_overflow for the new verifier

[Benjamin Tissoires <bentiss@kernel.org>]

The new verifier in the bpf-next branch is now capable of detecting the
overflow that was triggered by test_rdesc_fixup_get_data_overflow.
This is better in terms of UI, but now the test is failing and should be
marked as expected to fail.

Add a new parameter to load_programs() when we expect the test to fail,
and dynamically validate the test by checkcing if it loads (it should
fail to load with new verifier), but if it still loads, HID-BPF should
detect the overflow itself and return an error in hid_bpf_get_data().

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
---
 tools/testing/selftests/hid/hid_bpf.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c
index 069ebdbb4d1c..7ab86296ff23 100644
--- a/tools/testing/selftests/hid/hid_bpf.c
+++ b/tools/testing/selftests/hid/hid_bpf.c
@@ -67,14 +67,17 @@ struct test_program {
 	int insert_head;
 };
 #define LOAD_PROGRAMS(progs) \
-	load_programs(progs, ARRAY_SIZE(progs), _metadata, self, variant)
+	load_programs(progs, ARRAY_SIZE(progs), false, _metadata, self, variant)
+#define LOAD_PROGRAMS_MAY_FAIL(progs) \
+	load_programs(progs, ARRAY_SIZE(progs), true, _metadata, self, variant)
 #define LOAD_BPF \
-	load_programs(NULL, 0, _metadata, self, variant)
-static void load_programs(const struct test_program programs[],
-			  const size_t progs_count,
-			  struct __test_metadata *_metadata,
-			  FIXTURE_DATA(hid_bpf) * self,
-			  const FIXTURE_VARIANT(hid_bpf) * variant)
+	load_programs(NULL, 0, false, _metadata, self, variant)
+static int load_programs(const struct test_program programs[],
+			 const size_t progs_count,
+			 bool load_may_fail,
+			 struct __test_metadata *_metadata,
+			 FIXTURE_DATA(hid_bpf) * self,
+			 const FIXTURE_VARIANT(hid_bpf) * variant)
 {
 	struct bpf_map *iter_map;
 	int err = -EINVAL;
@@ -128,6 +131,9 @@ static void load_programs(const struct test_program programs[],
 	}
 
 	err = hid__load(self->skel);
+	if (err && load_may_fail)
+		return err;
+
 	ASSERT_OK(err) TH_LOG("hid_skel_load failed: %d", err);
 
 	for (int i = 0; i < progs_count; i++) {
@@ -147,6 +153,7 @@ static void load_programs(const struct test_program programs[],
 
 	self->hidraw_fd = open_hidraw(&self->hid);
 	ASSERT_GE(self->hidraw_fd, 0) TH_LOG("open_hidraw");
+	return 0;
 }
 
 /*
@@ -904,7 +911,9 @@ TEST_F(hid_bpf, test_rdesc_fixup_get_data_overflow)
 		{ .name = "hid_rdesc_fixup_get_data_overflow" },
 	};
 
-	LOAD_PROGRAMS(progs);
+	/* newer verifier can detect the overflow at load time */
+	if (LOAD_PROGRAMS_MAY_FAIL(progs))
+		return;
 
 	ASSERT_EQ(self->skel->bss->get_data_overflow_check, 1);
 }

-- 
2.55.0