Re: [PATCH] kcov: convert kcov.refcount to refcount_t

Dmitry Vyukov
2019-01-21T17:07:18Z

On Mon, Jan 21, 2019 at 3:07 PM Reshetova, Elena
<elena.reshetova@intel.com> wrote:
>
> > Just to check, has this been tested with CONFIG_REFCOUNT_FULL and
> > > something poking kcov?
> > >
> > > Given lib/refcount.c is instrumented, the refcount_*() calls will
> > > recurse back into the kcov code. It looks like that's fine, given these
> > > are only manipulated in setup/teardown paths, but it would be nice to be
> > > sure.
> >
> > A simple program using KCOV is available here:
> > https://elixir.bootlin.com/linux/v5.0-rc3/source/Documentation/dev-
> > tools/kcov.rst#L42
> > or here (it's like strace but collects and prints KCOV coverage):
> > https://github.com/google/syzkaller/blob/master/tools/kcovtrace/kcovtrace.c
> >
>
> No, this one hasn't gone via any particular testing apart
> the tests that zero day runs automatically (like boot tests, etc.) since normally
> it is hard for me to know how exactly to test a particular component in a meaningful
> way.
>
> But I can try to test with the above example now, if it helps!

We really need automated tests but I wan't able to figure out how to
write/run kernel tests. Sorry about that. Need to try again. I've
filed https://bugzilla.kernel.org/show_bug.cgi?id=202363 for this.