On Fri, Jul 10, 2020 at 10:00 AM Arnaldo Carvalho de Melo
<arnaldo.melo@xxxxxxxxx> wrote:
>
> Em Wed, Jul 01, 2020 at 08:21:13AM -0700, Alexei Starovoitov escreveu:
> > On Wed, Jul 1, 2020 at 2:34 AM Daniel Borkmann <daniel@xxxxxxxxxxxxx> wrote:
> > >
> > > +1, I think augmenting mid-term would be the best given check_sleepable_blacklist()
> > > is rather a very fragile workaround^hack and it's also a generic lsm/sec hooks issue
> >
> > I tried to make that crystal clear back in march during bpf virtual conference.
> > imo whitelist is just as fragile as blacklist. Underlying
> > implementation can change.
> >
> > > (at least for BPF_PROG_TYPE_LSM type & for the sake of documenting it for other LSMs).
> > > Perhaps there are function attributes that could be used and later retrieved via BTF?
> >
> > Even if we convince gcc folks to add another function attribute it
> > won't appear in dwarf.
>
> Warning, hack ahead!
>
> Perhaps we could do that with some sort of convention, i.e. define some
> type and make a function returning that type to have the desired
> attribute?
>
> I.e.
>
> typedef __attribute__foo__int int;
>
> __attribute__foo__int function_bla(...)
> {
> }
>
> ?
What about lsm hooks returning void ?
I guess for lsm we can hack something like that,
but for __rcu and __user that won't really work.
The kernel changes will be too massive.
