Make sure that bpf_prog_test_run returns the correct length
in the size_out argument and that the kernel respects the
output size hint. Also check that errno indicates ENOSPC.
Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
---
tools/testing/selftests/bpf/test_progs.c | 34 ++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 299938603cb6..92e48c2ba2c6 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -124,6 +124,39 @@ static void test_pkt_access(void)
bpf_object__close(obj);
}
+static void test_output_size_hint(void)
+{
+ const char *file = "./test_pkt_access.o";
+ struct bpf_object *obj;
+ __u32 retval, size, duration;
+ int err, prog_fd;
+ char buf[10];
+
+ err = bpf_prog_load(file, BPF_PROG_TYPE_SCHED_CLS, &obj, &prog_fd);
+ if (CHECK(err, "load", "err %d errno %d\n", err, errno))
+ return;
+
+ memset(buf, 0, sizeof(buf));
+
+ size = 5;
+ err = bpf_prog_test_run(prog_fd, 1, &pkt_v4, sizeof(pkt_v4),
+ buf, &size, &retval, &duration);
+ CHECK(err != -1 || errno != ENOSPC || retval, "run",
+ "err %d errno %d retval %d\n",
+ err, errno, retval);
+
+ duration = 0;
+
+ CHECK(size != sizeof(pkt_v4), "out_size",
+ "incorrect output size, want %lu have %u\n",
+ sizeof(pkt_v4), size);
+
+ CHECK(buf[5] != 0, "overflow",
+ "prog_test_run ignored size hint\n");
+
+ bpf_object__close(obj);
+}
+
static void test_xdp(void)
{
struct vip key4 = {.protocol = 6, .family = AF_INET};
@@ -1847,6 +1880,7 @@ int main(void)
jit_enabled = is_jit_enabled();
test_pkt_access();
+ test_output_size_hint();
test_xdp();
test_xdp_adjust_tail();
test_l4lb_all();
--
2.17.1
