Fix regression in libbpf, introduced by XDP link change, which causes XDP
programs to fail to be loaded into kernel due to specified BPF_XDP
expected_attach_type. While kernel doesn't enforce expected_attach_type for
BPF_PROG_TYPE_XDP, some old kernels already support XDP program, but they
don't yet recognize expected_attach_type field in bpf_attr, so setting it to
non-zero value causes program load to fail.
Luckily, libbpf already has a mechanism to deal with such cases, so just make
expected_attach_type optional for XDP programs.
Fixes:
dc8698cac7aa ("libbpf: Add support for BPF XDP link")
Reported-by: Nikita Shirokov <tehnerd@tehnerd.com>
Reported-by: Udip Pant <udippant@fb.com>
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200924171705.3803628-1-andriin@fb.com
BPF_XDP_DEVMAP),
BPF_EAPROG_SEC("xdp_cpumap/", BPF_PROG_TYPE_XDP,
BPF_XDP_CPUMAP),
- BPF_EAPROG_SEC("xdp", BPF_PROG_TYPE_XDP,
+ BPF_APROG_SEC("xdp", BPF_PROG_TYPE_XDP,
BPF_XDP),
BPF_PROG_SEC("perf_event", BPF_PROG_TYPE_PERF_EVENT),
BPF_PROG_SEC("lwt_in", BPF_PROG_TYPE_LWT_IN),