On Mon, Nov 02, 2020 at 11:38:14PM -0700, Nathan Chancellor wrote:
> On Tue, Nov 03, 2020 at 06:55:21AM +0200, Jarkko Sakkinen wrote:
> > On Wed, Sep 02, 2020 at 03:59:05PM -0700, Nick Desaulniers wrote:
> > > During Plumbers 2020, we voted to just support the latest release of
> > > Clang for now.  Add a compile time check for this.
> > > 
> > > We plan to remove workarounds for older versions now, which will break
> > > in subtle and not so subtle ways.
> > > 
> > > Suggested-by: Sedat Dilek <sedat.dilek@gmail.com>
> > > Suggested-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Suggested-by: Kees Cook <keescook@chromium.org>
> > > Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> > > Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
> > > Reviewed-by: Kees Cook <keescook@chromium.org>
> > > Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
> > > Reviewed-by: Sedat Dilek <sedat.dilek@gmail.com>
> > > Acked-by: Marco Elver <elver@google.com>
> > > Acked-by: Nathan Chancellor <natechancellor@gmail.com>
> > > Acked-by: Sedat Dilek <sedat.dilek@gmail.com>
> > > Link: https://github.com/ClangBuiltLinux/linux/issues/9
> > > Link: https://github.com/ClangBuiltLinux/linux/issues/941
> > > ---
> > >  include/linux/compiler-clang.h | 8 ++++++++
> > >  1 file changed, 8 insertions(+)
> > > 
> > > diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> > > index cee0c728d39a..230604e7f057 100644
> > > --- a/include/linux/compiler-clang.h
> > > +++ b/include/linux/compiler-clang.h
> > > @@ -3,6 +3,14 @@
> > >  #error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
> > >  #endif
> > >  
> > > +#define CLANG_VERSION (__clang_major__ * 10000	\
> > > +		     + __clang_minor__ * 100	\
> > > +		     + __clang_patchlevel__)
> > > +
> > > +#if CLANG_VERSION < 100001
> > > +# error Sorry, your version of Clang is too old - please use 10.0.1 or newer.
> > > +#endif
> > 
> > 
> > I'm trying to compile a BPF enabled test kernel for a live system and I
> > get this error even though I have much newer clang:
> > 
> > ➜  ~ (master) ✔ clang --version          
> > Ubuntu clang version 11.0.0-2
> > Target: x86_64-pc-linux-gnu
> > Thread model: posix
> > InstalledDir: /usr/bin
> > 
> > Tried to Google for troubleshooter tips but this patch is basically the
> > only hit I get :-)
> 
> Do you have a .config and command to reproduce the error?

Attached.

> Cheers,
> Nathan

/Jarkko