Re: kcsan -Wmaybe-uninitialized warning in ntfs3

Marco Elver
2026-04-22T11:35:52Z

On Wed, 22 Apr 2026 at 10:23, Marco Elver <elver@google.com> wrote:
>
> On Wed, 22 Apr 2026 at 10:00, Arnd Bergmann <arnd@arndb.de> wrote:
> >
> > On Tue, Apr 21, 2026, at 21:12, Arnd Bergmann wrote:
> > > On Tue, Apr 21, 2026, at 21:06, Marco Elver wrote:
> > >> On Tue, 21 Apr 2026 at 17:26, Marco Elver <elver@google.com> wrote:
> > >> [...]
> > >>> > To me, 2 makes more sense. The attribute requires gcc-11 or higher,
> > >>> > so you need to wrap that in a compiler version specific macro,
> > >>> > but since I only saw the warning with gcc-12 and higher, that
> > >>> > should be fine.
> > >>
> > >> Kindly test if you can:
> > >> https://lore.kernel.org/all/20260421190351.1976329-1-elver@google.com/
> > >
> > > Applied to my randconfig tree and verified that this fixes the
> > > known warning (only one out of about 200 random configs). I'll
> > > let you know if something comes up by tomorrow.
> >
> > Unfortunately, there are new warnings after your patches using
> > gcc-11. In 500 randconfig builds with that compiler, I saw 7
> > configurations failing with one of these four messages:
>
> Looks like a compiler bug to me; can you check gcc-12+ ? Maybe we need
> to allow the __access attribute only for later GCC versions.

I can also see this warning with later GCC - so I'll give up on the
__attribute__((access)) version and instead suppress warnings.