* Andrey Ryabinin <aryabi...@virtuozzo.com> wrote:
> On 10/05/2015 07:39 PM, Andi Kleen wrote:
> >> But, I think I have the solution.
> >> We could have some blacklist - list of function names which we should be
> >> ignored.
> >> In kasan_report() we could resolve return address to function name and
> >> compare it with name in list.
> >> If name in list -> ignore report.
> >
> > I think annotating statements is cleaner than functions, even if it
> > is more code. Much better documentation
> >
>
> I agree with that, that's why I suggested to add READ_ONCE_NOCHECK():
> READ_ONCE_NOCHECK()
> {
> kasan_disable_current();
> READ_ONCE();
> kasan_enable_current();
> }
>
> Anywone objects?
Sounds good to me! As long as it's hidden from plain .c files I'm a happy
camper.
This should probably also be faster for KASAN than triggering a warning and
having
to parse a blacklist, right?
> > If disabling with an attribute doesn't work, you could put it into a
> > special
> > section with __attribute__((section ...)) and check the start/end symbol
> > before reporting. That's how kprobes solves similar issues. It also has the
> > advantage that it stops inlining.
>
> Yes, it might be better. Although, because of broken -fconserve-stack, this
> may
> not work in some cases - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63533
> Function splitter may split original function into two parts and it always
> puts
> one split part in default .text section.
We do a _ton_ of such section tricks in the kernel (all of exception handling
is
based on that) - if that's broken by -fconserve-stack then the kernel is broken
much more widely.
So unless KASAN wants to do something special here you can rely on sections
just
fine.
Thanks,
Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
