Re: kasan patches

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Aug 14, 2018 at 02:44:19PM +0200, Andrey Konovalov wrote:
> On Tue, Aug 14, 2018 at 9:37 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> > On Tue, Aug 14, 2018 at 09:24:29AM +0200, Greg KH wrote:
> >> On Mon, Aug 13, 2018 at 02:25:12PM -0700, Nick Desaulniers wrote:
> >> > On Sat, Aug 11, 2018 at 9:40 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> >> > >
> >> > > On Mon, Aug 06, 2018 at 02:08:32PM -0700, Nick Desaulniers wrote:
> >> > > > These patches are needed for kasan+clang support.  I confirmed they
> >> > > > apply cleanly in order (top to bottom):
> >> > > >
> >> > > > 4.9:
> >> > > > commit c5caf21ab0cf8 ("kasan: turn on -fsanitize-address-use-after-scope")
> >> > > > commit 0e410e158e5b ("kasan: don't emit builtin calls when sanitization is off")
> >> > >
> >> > > By applying these, I get a ton of new build warnings, so I can't add
> >> > > them :(
> >> >
> >> > What? Such innocent patches.
> >> >
> >> > $ git remote add stable
> >> > git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
> >> > $ git checkout -b 4.9-stable-kasan stable/linux-4.9.y
> >> > <git log shows 4.9.118>
> >> > $ git cherry-pick c5caf21ab0cf8
> >> > $ git cherry-pick 0e410e158e5b
> >> > $ make defconfig
> >> > $ make -j46
> >> >
> >> > I get -Wstringop-truncation, -Wstringop-overflow=,
> >> > -Wpacked-not-aligned, -Warray-bounds warnings with gcc-8 with or
> >> > without these patches.
> >> >
> >> > Can you share your config, or what the warning was?  Did I checkout
> >> > the wrong branch?
> >>
> >> I used 'make allmodconfig' on a x86 Fedora 27 release which is using gcc
> >> 7.3.1.  Adding those patches adds a ton of warnings.  Let me go do a
> >> test build and send you the full log...
> >
> > Attached is the full build log.  Before those 2 patches were added, no
> > build warnings.  Afterward, I now have 148 build warnings.  So something
> > is not right here.
> 
> I think the issue here is that e7c52b84fb ("kasan: rework Kconfig
> settings") should have been backported after c5caf21ab0cf8 ("kasan:
> turn on -fsanitize-address-use-after-scope"). You'll need to
> "rebackport" the former one (hide use-after-scope under
> CONFIG_KASAN_EXTRA and set FRAME_WARN to 3072 with KASAN_EXTRA).

Again, if someone could send me a patch series that are properly
backported, it would make everything a lot easier and allow these
patches to actually be applied :)

thanks,

greg k-h