Re: [PATCH v13 1/7] kcfi: Introduce KCFI typeinfo mangling API

[Kees Cook <kees@kernel.org>]

On Wed, Jul 15, 2026 at 12:06:17PM -0700, Kees Cook wrote:
> On Sat, Jun 27, 2026 at 03:00:42PM -0700, Andrea Pinski wrote:
> > On Thu, Jun 18, 2026 at 1:45 PM Kees Cook <kees@kernel.org> wrote:
> > > [...]
> > > +
> > > +    printf("\n================================================================\n");
> > > +    printf("Passed: %d Failed: %d (%d total tests)\n", pass, fail, pass + fail);
> > > +    return fail;
> > > +}
> > 
> > It would be a good idea to add a random generated testing here. See
> > testsuite/objc.dg/gnu-encoding and testsuite/gcc.dg/compat for
> > examples.
> 
> Okay, thanks for the pointer; I'll see what I can come up with. I
> generally dislike random testing since they may appear to be "flaky"
> when they trip, but I'll give it a shot.

I don't see anything we can do valuably here. There's no round-trip
parsing going on (there's no independent oracle). For the existing
mangling tests, I have hard-coded all the expected strings/hashes. I have
gone through the TYPE enums, though, and added a few other missed types
for the mangler. But I built a python-based fuzzer anyway, just to see if
I could find any other combinatorial ICEs, in case I missed some mixture,
and I could only crash the ToT GCC frontend. :P It's okay in 16.1?

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126284

-Kees

-- 
Kees Cook