Add a subprogram to BPF object file that otherwise has no entry BPF
programs to validate that libbpf can still load this correctly.
Until this was fixed, user could expect this very confusing error message:
libbpf: prog 'dangling_subprog': missing BPF prog type, check ELF section name '.text'
libbpf: prog 'dangling_subprog': failed to load: -22
libbpf: failed to load object 'struct_ops_detach'
libbpf: failed to load BPF skeleton 'struct_ops_detach': -22
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241010211731.4121837-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Verify whether a user space program is informed through epoll with EPOLLHUP
when a struct_ops object is detached.
The BPF code in selftests/bpf/progs/struct_ops_module.c has become
complex. Therefore, struct_ops_detach.c has been added to segregate the BPF
code for detachment tests from the BPF code for other tests based on the
recommendation of Andrii Nakryiko.
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
Link: https://lore.kernel.org/r/20240530065946.979330-6-thinker.li@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
