Re: KCSAN Support on ARM64 Kernel

[Marco Elver <elver@google.com>]

We're in the process of upstreaming KCSAN, which will simplify a lot
of things including Arm64 support. So far KCSAN is not yet in
mainline, but I assume when that happens (if things go well, very
soon) it should be trivial to add Arm64 support based on Mark's
prototype.

Thanks,
-- Marco

On Mon, 2 Dec 2019 at 06:07, <sgrover@codeaurora.org> wrote:
>
> Hi All,
>
> Is there any update in Arm64 support of KCSAN.
>
> Regards,
> Sachin Grover
>
> -----Original Message-----
> From: Mark Rutland <mark.rutland@arm.com>
> Sent: Monday, 14 October, 2019 3:50 PM
> To: Marco Elver <elver@google.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>; sgrover@codeaurora.org; kasan-dev <kasan-dev@googlegroups.com>; LKML <linux-kernel@vger.kernel.org>; Paul E. McKenney <paulmck@linux.ibm.com>; Will Deacon <willdeacon@google.com>; Andrea Parri <parri.andrea@gmail.com>; Alan Stern <stern@rowland.harvard.edu>
> Subject: Re: KCSAN Support on ARM64 Kernel
>
> On Mon, Oct 14, 2019 at 11:09:40AM +0200, Marco Elver wrote:
> > On Mon, 14 Oct 2019 at 10:40, Dmitry Vyukov <dvyukov@google.com> wrote:
> > >
> > > On Mon, Oct 14, 2019 at 7:11 AM <sgrover@codeaurora.org> wrote:
> > > >
> > > > Hi Dmitry,
> > > >
> > > > I am from Qualcomm Linux Security Team, just going through KCSAN
> > > > and found that there was a thread for arm64 support
> > > > (https://lkml.org/lkml/2019/9/20/804).
> > > >
> > > > Can you please tell me if KCSAN is supported on ARM64 now? Can I
> > > > just rebase the KCSAN branch on top of our let’s say android
> > > > mainline kernel, enable the config and run syzkaller on that for
> > > > finding race conditions?
> > > >
> > > > It would be very helpful if you reply, we want to setup this for
> > > > finding issues on our proprietary modules that are not part of
> > > > kernel mainline.
> > > >
> > > > Regards,
> > > >
> > > > Sachin Grover
> > >
> > > +more people re KCSAN on ARM64
> >
> > KCSAN does not yet have ARM64 support. Once it's upstream, I would
> > expect that Mark's patches (from repo linked in LKML thread) will just
> > cleanly apply to enable ARM64 support.
>
> Once the core kcsan bits are ready, I'll rebase the arm64 patch atop.
> I'm expecting some things to change as part of review, so it'd be great to see that posted ASAP.
>
> For arm64 I'm not expecting major changes (other than those necessary to handle the arm64 atomic rework that went in to v5.4-rc1)
>
> FWIW, I was able to run Syzkaller atop of my arm64/kcsan branch, but it's very noisy as it has none of the core fixes.
>
> Thanks,
> Mark.
>