On Fri, Nov 29, 2019 at 3:52 PM Andrey Konovalov <andreyknvl@xxxxxxxxxx> wrote: > > On Fri, Nov 22, 2019 at 12:27 PM <glider@xxxxxxxxxx> wrote: > > > > We assume nothing interesting could happen in stackdepot, and save some > > memory by not tracking stackdepot allocations with KMSAN. > > I think it makes sense to clarify here that "nothing interesting" > means no uninitialized memory can come from stackdepot or something > like that. Agreed. Will update the patch description. I've also noticed this patch does nothing to ensure the allocations are performed with __GFP_NO_KMSAN_SHADOW. > > > > Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> > > Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx> > > Cc: Jens Axboe <axboe@xxxxxxxxx> > > Cc: Andy Lutomirski <luto@xxxxxxxxxx> > > Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx> > > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > > Cc: Christoph Hellwig <hch@xxxxxx> > > Cc: linux-mm@xxxxxxxxx > > --- > > > > Change-Id: Ic3ec9b3dff3fff2732d874508a3582fb26ff0b1f > > --- > > lib/stackdepot.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/lib/stackdepot.c b/lib/stackdepot.c > > index e2f000a9fad8..2b053c429454 100644 > > --- a/lib/stackdepot.c > > +++ b/lib/stackdepot.c > > @@ -294,7 +294,8 @@ depot_stack_handle_t stack_depot_save(unsigned long *entries, > > * contexts and I/O. > > */ > > alloc_flags &= ~GFP_ZONEMASK; > > - alloc_flags &= (GFP_ATOMIC | GFP_KERNEL); > > + alloc_flags &= (GFP_ATOMIC | GFP_KERNEL | > > + __GFP_NO_KMSAN_SHADOW); > > alloc_flags |= __GFP_NOWARN; Should have added __GFP_NO_KMSAN_SHADOW here. > > page = alloc_pages(alloc_flags, STACK_ALLOC_ORDER); > > if (page) > > -- > > 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
