2024-06-01 13:32:45

by Mateusz Guzik

Subject: [PATCH] bpf: plug a warn about bpf_session_cookie without CONFIG_FPROBE

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 <[email protected]>
---

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

2024-06-01 14:45:25

by Jiri Olsa

Subject: Re: [PATCH] bpf: plug a warn about bpf_session_cookie without CONFIG_FPROBE

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 <[email protected]>
> ---
>
> 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/[email protected]/

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
>
>