RE: [PATCH] Coccinelle report script for refcounters

From: Reshetova, Elena
Date: Tue Jul 18 2017 - 05:30:20 EST


> On Tue, 18 Jul 2017, Elena Reshetova wrote:
>
> > The below script can be used to detect potential misusage
> > of atomic_t type and API for reference counting purposes.
> > Now when we have a dedicated refcount_t type and API with
> > security protection implemented, people should be using it
> > instead.
> >
> > Currently it still reports many occurences since we are
> > nowhere near the end of our kernel-wide conversion execrise,
> > but hopefully after couple of cycles more, the amount of
> > output would be much more limited.
> >
> > Each script result must be analysed manually before any
> > conversion, since refcount_t might not suit for certain
> > purposes (for example if an object is not always destroyed
> > upon refcounter reaching zero, if increments from zero are
> > allowed in the code etc.)
> >
> > As we go further and get less results in output, we will
> > improve the pattern to detect conversion cases more precisely.
>
> The regexps are the best you can do?

They are simple and so far they were sufficient for the purpose since
they found pretty much all the cases we are aware about. I was thinking
on working to improve the pattern later on after we merge the bulk of
conversions and I have some cycles free on that front.

What would you suggest to do instead of regexps?

Best Regards,
Elena.

>
> julia
>
> >
> > Elena Reshetova (1):
> > Coccinelle: add atomic_as_refcounter script
> >
> > scripts/coccinelle/api/atomic_as_refcounter.cocci | 102
> ++++++++++++++++++++++
> > 1 file changed, 102 insertions(+)
> > create mode 100644 scripts/coccinelle/api/atomic_as_refcounter.cocci
> >
> > --
> > 2.7.4
> >
> >