Re: [PATCH 1/3] kcov: support comparison operands collection

From: Mark Rutland
Date: Thu Aug 31 2017 - 05:33:15 EST


On Wed, Aug 30, 2017 at 09:08:43PM +0200, Dmitry Vyukov wrote:
> On Wed, Aug 30, 2017 at 8:23 PM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> > On Wed, Aug 30, 2017 at 06:23:29PM +0200, Dmitry Vyukov wrote:
> >> From: Victor Chibotaru <tchibo@xxxxxxxxxx>
> >>
> >> Enables kcov to collect comparison operands from instrumented code.
> >> This is done by using Clang's -fsanitize=trace-cmp instrumentation
> >> (currently not available for GCC).

> >> Clang instrumentation:
> >> https://clang.llvm.org/docs/SanitizerCoverage.html#tracing-data-flow
> >
> > How stable is this?
> >
> > The comment at the end says "This interface is a subject to change."
>
> The intention is that this is not subject to change anymore (since we
> are using it in kernel).
> I've mailed change to docs: https://reviews.llvm.org/D37303

Ok; thanks for confirming.

> FWIW, there is patch in flight that adds this instrumentation to gcc:
> https://groups.google.com/forum/#!topic/syzkaller/CSLynn6nI-A
> It seems to be stalled on review phase, though.

Let's hope it gets unblocked soon. :)

Thanks,
Mark.