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Author SHA1 Message Date
Andrii Nakryiko
fd63729cc0 selftests/bpf: Fix unused attribute usage in subprogs_unused test
Correct attribute name is "unused". maybe_unused is a C++17 addition.
This patch fixes compilation warning during selftests compilation.

Fixes: 197afc6314 ("libbpf: Don't attempt to load unused subprog as an entry-point BPF program")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20201111231215.1779147-1-andrii@kernel.org
2020-11-12 09:13:49 -08:00
Andrii Nakryiko
197afc6314 libbpf: Don't attempt to load unused subprog as an entry-point BPF program
If BPF code contains unused BPF subprogram and there are no other subprogram
calls (which can realistically happen in real-world applications given
sufficiently smart Clang code optimizations), libbpf will erroneously assume
that subprograms are entry-point programs and will attempt to load them with
UNSPEC program type.

Fix by not relying on subcall instructions and rather detect it based on the
structure of BPF object's sections.

Fixes: 9a94f277c4 ("tools: libbpf: restore the ability to load programs from .text section")
Reported-by: Dmitrii Banshchikov <dbanschikov@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20201107000251.256821-1-andrii@kernel.org
2020-11-09 22:15:23 +01:00