On Mon, Dec 2, 2019 at 4:51 PM Marco Elver <elver@xxxxxxxxxx> wrote: > > On Fri, 22 Nov 2019 at 12:28, <glider@xxxxxxxxxx> wrote: > > > > Disable the efficient 8-byte reading under KMSAN to avoid false positives. > > > > Signed-off-by: Alexander Potapenko <glider@xxxxxxxxxx> > > To: Alexander Potapenko <glider@xxxxxxxxxx> > > Cc: Vegard Nossum <vegard.nossum@xxxxxxxxxx> > > Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx> > > Cc: linux-mm@xxxxxxxxx > > > > --- > > > > Change-Id: I25d1acf5c3df6eff85894cd94f5ddbe93308271c > > --- > > lib/string.c | 5 ++++- > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > diff --git a/lib/string.c b/lib/string.c > > index 08ec58cc673b..15efdc51bda6 100644 > > --- a/lib/string.c > > +++ b/lib/string.c > > @@ -186,7 +186,10 @@ ssize_t strscpy(char *dest, const char *src, size_t count) > > if (count == 0 || WARN_ON_ONCE(count > INT_MAX)) > > return -E2BIG; > > > > -#ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS > > +/** > > Why a doc comment? Will fix, thanks! > > + * Disable the efficient 8-byte reading under KMSAN to avoid false positives. > > + */ > > AFAIK the CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS case is about > unaligned accesses crossing page boundaries. In the #else case it's > still going to do word-at-a-time if both src and dest are aligned, so > the comment above is somewhat inaccurate. Yes, this makes little sense. Reading word-at-a-time shouldn't induce any errors, although it may generate redundant stack IDs for values that will never be used. I'll try to drop this patch. > > +#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && !defined(CONFIG_KMSAN) > > /* > > * If src is unaligned, don't cross a page boundary, > > * since we don't know if the next page is mapped. > > -- > > 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
