| Message ID | 20201001051339.2549085-1-yhs@fb.com |
|---|---|
| State | New |
| Headers | show |
| Series | [bpf,v3] bpf: fix "unresolved symbol" build error with resolve_btfids | expand |
On Wed, Sep 30, 2020 at 10:13:39PM -0700, Yonghong Song wrote: > Michal reported a build failure likes below: > BTFIDS vmlinux > FAILED unresolved symbol tcp_timewait_sock > make[1]: *** [/.../linux-5.9-rc7/Makefile:1176: vmlinux] Error 255 > > This error can be triggered when config has CONFIG_NET enabled > but CONFIG_INET disabled. In this case, there is no user of > structs inet_timewait_sock and tcp_timewait_sock and hence vmlinux BTF > types are not generated for these two structures. > > To fix the problem, let us force BTF generation for these two > structures with BTF_TYPE_EMIT. Acked-by: Martin KaFai Lau <kafai@fb.com>
diff --git a/net/core/filter.c b/net/core/filter.c index 21eaf3b182f2..b5f3faac5e3b 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -9558,6 +9558,12 @@ const struct bpf_func_proto bpf_skc_to_tcp_sock_proto = { BPF_CALL_1(bpf_skc_to_tcp_timewait_sock, struct sock *, sk) { + /* BTF types for tcp_timewait_sock and inet_timewait_sock are not + * generated if CONFIG_INET=n. Trigger an explicit generation here. + */ + BTF_TYPE_EMIT(struct inet_timewait_sock); + BTF_TYPE_EMIT(struct tcp_timewait_sock); + #ifdef CONFIG_INET if (sk && sk->sk_prot == &tcp_prot && sk->sk_state == TCP_TIME_WAIT) return (unsigned long)sk;
Michal reported a build failure likes below: BTFIDS vmlinux FAILED unresolved symbol tcp_timewait_sock make[1]: *** [/.../linux-5.9-rc7/Makefile:1176: vmlinux] Error 255 This error can be triggered when config has CONFIG_NET enabled but CONFIG_INET disabled. In this case, there is no user of structs inet_timewait_sock and tcp_timewait_sock and hence vmlinux BTF types are not generated for these two structures. To fix the problem, let us force BTF generation for these two structures with BTF_TYPE_EMIT. Fixes: fce557bcef11 ("bpf: Make btf_sock_ids global") Reported-by: Michal Kubecek <mkubecek@suse.cz> Signed-off-by: Yonghong Song <yhs@fb.com> --- net/core/filter.c | 6 ++++++ 1 file changed, 6 insertions(+) Changelog: v2 -> v3: . instead of avoiding generating BTF types which is more complex, just always generating these BTF types (under CONFIG_NET). v1 -> v2: . For unsupported socket times, using BTF_ID_UNUSED to keep the id as 0. (Martin)