Re: [PATCH bpf-next v3 1/7] bpf: Consolidate locks and reference state in verifier state

[Eduard Zingerman <eddyz87@gmail.com>]

On Thu, 2024-11-28 at 03:54 +0100, Kumar Kartikeya Dwivedi wrote:

[...]

> > > --- a/kernel/bpf/log.c
> > > +++ b/kernel/bpf/log.c
> > > @@ -756,6 +756,7 @@ static void print_reg_state(struct bpf_verifier_env *env,
> > >  void print_verifier_state(struct bpf_verifier_env *env, const struct bpf_func_state *state,
> > >                         bool print_all)
> > >  {
> > > +     struct bpf_verifier_state *vstate = env->cur_state;
> > 
> > This is not always true.
> > For example, __mark_chain_precision does 'print_verifier_state(env, func, true)'
> > for func obtained as 'func = st->frame[fr];' where 'st' iterates over parents
> > of env->cur_state.
> 
> Looking through the code, I'm thinking the only proper fix is
> explicitly passing in the verifier state, I was hoping there would be
> a link from func_state -> verifier_state but it is not the case.
> Regardless, explicitly passing in the verifier state is probably cleaner. WDYT?

Seems like it is (I'd also pass the frame number, instead of function
state pointer, just to make it clear where the function state comes from,
but feel free to ignore this suggestion).

[...]