On 7/21/20 3:07 AM, Jakub Sitnicki wrote:
> When CONFIG_NET is set but CONFIG_INET isn't, build fails with:
>
> ld: kernel/bpf/net_namespace.o: in function `netns_bpf_attach_type_unneed':
> kernel/bpf/net_namespace.c:32: undefined reference to `bpf_sk_lookup_enabled'
> ld: kernel/bpf/net_namespace.o: in function `netns_bpf_attach_type_need':
> kernel/bpf/net_namespace.c:43: undefined reference to `bpf_sk_lookup_enabled'
>
> This is because without CONFIG_INET bpf_sk_lookup_enabled symbol is not
> available. Wrap references to bpf_sk_lookup_enabled with preprocessor
> conditionals.
>
> Fixes: 1559b4aa1db4 ("inet: Run SK_LOOKUP BPF program on socket lookup")
> Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Reported-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Signed-off-by: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> # build-tested
Thanks.
> ---
> kernel/bpf/net_namespace.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/kernel/bpf/net_namespace.c b/kernel/bpf/net_namespace.c
> index 4e1bcaa2c3cb..71405edd667c 100644
> --- a/kernel/bpf/net_namespace.c
> +++ b/kernel/bpf/net_namespace.c
> @@ -28,9 +28,11 @@ DEFINE_MUTEX(netns_bpf_mutex);
> static void netns_bpf_attach_type_unneed(enum netns_bpf_attach_type type)
> {
> switch (type) {
> +#ifdef CONFIG_INET
> case NETNS_BPF_SK_LOOKUP:
> static_branch_dec(&bpf_sk_lookup_enabled);
> break;
> +#endif
> default:
> break;
> }
> @@ -39,9 +41,11 @@ static void netns_bpf_attach_type_unneed(enum netns_bpf_attach_type type)
> static void netns_bpf_attach_type_need(enum netns_bpf_attach_type type)
> {
> switch (type) {
> +#ifdef CONFIG_INET
> case NETNS_BPF_SK_LOOKUP:
> static_branch_inc(&bpf_sk_lookup_enabled);
> break;
> +#endif
> default:
> break;
> }
>
--
~Randy
