Re: [PATCH bpf-next 5/6] bpf: Improve tracing recursion prevention mechanism

[Alexei Starovoitov]

On Thu, Apr 27, 2023 at 8:36 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Thu, 27 Apr 2023 23:23:31 +0800
> Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> > > But I thought you can run a bpf_prog from another bpf_prog. So you don't
> > > want to prevent it. You need other logic to detect if it was not suppose to
> > > recurs.
> > >
> >
> > If so, we have to keep the prog->active to prevent it, then I'm not
> > sure if it is worth adding test_recursion_*().
>
> I thought that the whole point of this exercise was because the
> migrate_disable() itself could be traced (or call something that can), and
> that's outside of prog->active protection. Which the test_recursion_*()
> code was created for.

Not sure where did this come from.
migrate_enable/disable were added to deny list back in 2021.