On 20 Dec 2019, at 0:02, Andrii Nakryiko wrote:
On Thu, Dec 19, 2019 at 3:04 AM Eelco Chaudron <echaudro@xxxxxxxxxx>
wrote:
Add a test that will attach a FENTRY and FEXIT program to the XDP
test
program. It will also verify data from the XDP context on FENTRY and
verifies the return code on exit.
Signed-off-by: Eelco Chaudron <echaudro@xxxxxxxxxx>
---
.../testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c | 95
++++++++++++++++++++
.../testing/selftests/bpf/progs/test_xdp_bpf2bpf.c | 44 +++++++++
2 files changed, 139 insertions(+)
create mode 100644
tools/testing/selftests/bpf/prog_tests/xdp_bpf2bpf.c
create mode 100644
tools/testing/selftests/bpf/progs/test_xdp_bpf2bpf.c
[...]
+ /* Load XDP program to introspect */
+ err = bpf_prog_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
Please use BPF skeleton for this test. It will make it significantly
shorter and clearer. See other fentry_fexit selftest for example.
Trying to do this, however, I’m getting the following when trying to
execute the test:
test_xdp_bpf2bpf:PASS:pkt_skel_load 0 nsec
libbpf: fentry/_xdp_tx_iptunnel is not found in vmlinux BTF
libbpf: failed to load object 'test_xdp_bpf2bpf'
libbpf: failed to load BPF skeleton 'test_xdp_bpf2bpf': -2
test_xdp_bpf2bpf:FAIL:ftrace_skel_load ftrace skeleton failed
My program is straight forward following the fentry_fexit.c example:
pkt_skel = test_xdp__open_and_load();
if (CHECK(!pkt_skel, "pkt_skel_load", "test_xdp skeleton
failed\n"))
return;
map_fd = bpf_map__fd(pkt_skel->maps.vip2tnl);
bpf_map_update_elem(map_fd, &key4, &value4, 0);
/* Load eBPF trace program */
ftrace_skel = test_xdp_bpf2bpf__open_and_load();
if (CHECK(!ftrace_skel, "ftrace_skel_load", "ftrace skeleton
failed\n"))
goto out;
I assume this is due to the missing link from the XDP program to the
eBPF trace program.
Previously I did this trough:
+ DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
+ .attach_prog_fd = prog_fd,
+ );
+
+ tracer_obj = bpf_object__open_file("./test_xdp_bpf2bpf.o", &opts);
If I use this approach as before it works, i.e.:
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts,
.attach_prog_fd = pkt_fd,
);
ftrace_skel = test_xdp_bpf2bpf__open_opts(&opts);
if (CHECK(!ftrace_skel, "__open_opts”, "ftrace skeleton
failed\n"))
goto out;
if (CHECK(test_xdp_bpf2bpf__load(ftrace_skel), "__load",
"ftrace skeleton failed\n"))
goto out;
But I do not see this in the fentry_fexit.c example, guess I might be
missing something that is right in front of me :(
[...]
