On Mon, Jan 20, 2020 at 3:45 PM Dmitry Vyukov <dvyukov@xxxxxxxxxx> wrote:
>
> On Mon, Jan 20, 2020 at 3:19 PM Marco Elver <elver@xxxxxxxxxx> wrote:
> >
> > This adds instrumented.h, which provides generic wrappers for memory
> > access instrumentation that the compiler cannot emit for various
> > sanitizers. Currently this unifies KASAN and KCSAN instrumentation. In
> > future this will also include KMSAN instrumentation.
> >
> > Note that, copy_{to,from}_user require special instrumentation,
> > providing hooks before and after the access, since we may need to know
> > the actual bytes accessed (currently this is relevant for KCSAN, and is
> > also relevant in future for KMSAN).
> >
> > Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> > Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
> > ---
> > include/linux/instrumented.h | 153 +++++++++++++++++++++++++++++++++++
> > 1 file changed, 153 insertions(+)
> > create mode 100644 include/linux/instrumented.h
> >
> > diff --git a/include/linux/instrumented.h b/include/linux/instrumented.h
> > new file mode 100644
> > index 000000000000..9f83c8520223
> > --- /dev/null
> > +++ b/include/linux/instrumented.h
> > @@ -0,0 +1,153 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +
> > +/*
> > + * This header provides generic wrappers for memory access instrumentation that
> > + * the compiler cannot emit for: KASAN, KCSAN.
> > + */
> > +#ifndef _LINUX_INSTRUMENTED_H
> > +#define _LINUX_INSTRUMENTED_H
> > +
> > +#include <linux/compiler.h>
> > +#include <linux/kasan-checks.h>
> > +#include <linux/kcsan-checks.h>
> > +#include <linux/types.h>
> > +
> > +/**
> > + * instrument_read - instrument regular read access
> > + *
> > + * Instrument a regular read access. The instrumentation should be inserted
> > + * before the actual read happens.
> > + *
> > + * @ptr address of access
> > + * @size size of access
> > + */
>
> Based on offline discussion, that's what we add for KMSAN:
>
> > +static __always_inline void instrument_read(const volatile void *v, size_t size)
> > +{
> > + kasan_check_read(v, size);
> > + kcsan_check_read(v, size);
>
> KMSAN: nothing
KMSAN also has instrumentation in
copy_to_user_page/copy_from_user_page. Do we need to do anything for
KASAN/KCSAN for these functions?
