On Mon, Dec 2, 2019 at 11:03 AM Marco Elver <elver@xxxxxxxxxx> wrote: > > On Fri, 22 Nov 2019 at 12:27, <glider@xxxxxxxxxx> wrote: > > > > READ_ONCE_NOCHECK() is already used by KASAN to ignore memory accesses > > from e.g. stack unwinders. > > Define READ_ONCE_NOCHECK() for KMSAN so that it returns initialized > > values. This helps defeat false positives from leftover stack contents. > > > > Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> > > To: Alexander Potapenko <glider@xxxxxxxxxx> > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > > Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx> > > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > > Cc: linux-mm@xxxxxxxxx > > --- > > v3: > > - removed unnecessary #ifdef as requested by Mark Rutland > > > > Change-Id: Ib38369ba038ab3b581d8e45b81036c3304fb79cb > > --- > > include/linux/compiler.h | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/compiler.h b/include/linux/compiler.h > > index 5e88e7e33abe..99d40f31a2c3 100644 > > --- a/include/linux/compiler.h > > +++ b/include/linux/compiler.h > > @@ -270,9 +270,9 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s > > > > /* > > * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need > > - * to hide memory access from KASAN. > > + * to hide memory access from KASAN or KMSAN. > > */ > > -#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0) > > +#define READ_ONCE_NOCHECK(x) KMSAN_INIT_VALUE(__READ_ONCE(x, 0)) > > I think this needs: > #include <linux/kmsan-checks.h> > above. Ack, will include in v4. > > static __no_kasan_or_inline > > unsigned long read_word_at_a_time(const void *addr) > > -- > > 2.24.0.432.g9d3f5f5b63-goog > > -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
