On Fri, 2023-02-17 at 10:40 +0100, Jiri Olsa wrote:
> On Thu, Feb 16, 2023 at 12:59:31AM +0100, Ilya Leoshkevich wrote:
>
> SNIP
>
> > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> > index 71158a6786a1..47d390923610 100644
> > --- a/kernel/bpf/verifier.c
> > +++ b/kernel/bpf/verifier.c
> > @@ -2115,8 +2115,8 @@ static int add_subprog(struct
> > bpf_verifier_env *env, int off)
> > struct bpf_kfunc_desc {
> > struct btf_func_model func_model;
> > u32 func_id;
> > - s32 imm;
> > u16 offset;
> > + unsigned long addr;
> > };
> >
> > struct bpf_kfunc_btf {
> > @@ -2166,6 +2166,19 @@ find_kfunc_desc(const struct bpf_prog *prog,
> > u32 func_id, u16 offset)
> > sizeof(tab->descs[0]),
> > kfunc_desc_cmp_by_id_off);
> > }
> >
> > +int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id,
> > u16 offset,
> > + u8 **func_addr)
> > +{
> > + const struct bpf_kfunc_desc *desc;
> > +
> > + desc = find_kfunc_desc(prog, func_id, offset);
> > + if (!desc)
> > + return -EFAULT;
>
> should we warn here? this should alwayss succeed, right?
Hi Jiri!
This was discussed here:
https://lore.kernel.org/bpf/20230214212809.242632-1-iii@xxxxxxxxxxxxx/T/#m3a4748997d31f6840c50b0bf2ccafe9d24f9218f
The conclusion was that the existing code does not warn in situations
like this, so we should not warn here either.
Best regards,
Ilya
>
> jirka
>
> > +
> > + *func_addr = (u8 *)desc->addr;
> > + return 0;
> > +}
> > +
>
> SNIP
