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authorYonghong Song <yhs@fb.com>2020-09-30 22:13:39 -0700
committerDaniel Borkmann <daniel@iogearbox.net>2020-10-01 18:38:50 +0200
commitd82a532a611572d85fd2610ec41b5c9e222931b6 (patch)
tree97397fc70b916f554e8b39ff2ef8d790508c19a2
parenta59cf619787e628b31c310367f869fde26c8ede1 (diff)
downloadlinux-stericsson-d82a532a611572d85fd2610ec41b5c9e222931b6.tar.gz
bpf: Fix "unresolved symbol" build error with resolve_btfids
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 istructs 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> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20201001051339.2549085-1-yhs@fb.com
-rw-r--r--net/core/filter.c6
1 files changed, 6 insertions, 0 deletions
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;