Building a kernel without said option results in:
WARN: resolve_btfids: unresolved symbol bpf_session_cookie

This is a bare-minimum patch to sort it out.

There are other uses of the bpf_session_cookie thing spread out
thorought the file, they don't seem to break anything though.

Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
---

I don't care how this gets addressed, I just want the warning gone.
So I am not going to fight any ideas how to do it, as long as it gets
done.

 kernel/bpf/verifier.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 48f3a9acdef3..b081bdd6f477 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -11128,7 +11128,9 @@ BTF_ID(func, bpf_iter_css_task_new)
 #else
 BTF_ID_UNUSED
 #endif
+#ifdef CONFIG_FPROBES
 BTF_ID(func, bpf_session_cookie)
+#endif
 
 static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
 {
-- 
2.39.2

On Sat, Jun 01, 2024 at 03:32:23PM +0200, Mateusz Guzik wrote:
> Building a kernel without said option results in:
> WARN: resolve_btfids: unresolved symbol bpf_session_cookie
> 
> This is a bare-minimum patch to sort it out.
> 
> There are other uses of the bpf_session_cookie thing spread out
> thorought the file, they don't seem to break anything though.
> 
> Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
> ---
> 
> I don't care how this gets addressed, I just want the warning gone.
> So I am not going to fight any ideas how to do it, as long as it gets
> done.

it's fixed by:
  https://lore.kernel.org/bpf/20240531194500.2967187-1-jolsa@kernel.org/

thanks,
jirka

> 
>  kernel/bpf/verifier.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 48f3a9acdef3..b081bdd6f477 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -11128,7 +11128,9 @@ BTF_ID(func, bpf_iter_css_task_new)
>  #else
>  BTF_ID_UNUSED
>  #endif
> +#ifdef CONFIG_FPROBES
>  BTF_ID(func, bpf_session_cookie)
> +#endif
>  
>  static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
>  {
> -- 
> 2.39.2
> 
>