If boolean CONFIG_BPF_SYSCALL is enabled, kernel/bpf/syscall.c will
call flow_dissector functions from net/core/flow_dissector.c.
This causes this build failure if CONFIG_NET is disabled:
kernel/bpf/syscall.o: In function `__x64_sys_bpf':
syscall.c:(.text+0x3278): undefined reference to
`skb_flow_dissector_bpf_prog_attach'
syscall.c:(.text+0x3310): undefined reference to
`skb_flow_dissector_bpf_prog_detach'
kernel/bpf/syscall.o:(.rodata+0x3f0): undefined reference to
`flow_dissector_prog_ops'
kernel/bpf/verifier.o:(.rodata+0x250): undefined reference to
`flow_dissector_verifier_ops'
Analogous to other optional BPF program types in syscall.c, add stubs
if the relevant functions are not compiled and move the BPF_PROG_TYPE
definition in the #ifdef CONFIG_NET block.
Fixes: d58e468b11 ("flow_dissector: implements flow dissector BPF hook")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2dfd184abd