Re: [RFC v2 2/3] atomic: Specify alignment for atomic_t and atomic64_t

[Geert Uytterhoeven <geert@linux-m68k.org>]

Hi Finn,

On Mon, 22 Sept 2025 at 10:16, Finn Thain <fthain@linux-m68k.org> wrote:
> On Mon, 22 Sep 2025, Geert Uytterhoeven wrote:
> > This triggers a failure in kernel/bpf/rqspinlock.c:
> >
> > kernel/bpf/rqspinlock.c: In function ‘bpf_res_spin_lock’:
> > include/linux/compiler_types.h:572:45: error: call to
> > ‘__compiletime_assert_397’ declared with attribute error: BUILD_BUG_ON
> > failed: __alignof__(rqspinlock_t) != __alignof__(struct
> > bpf_res_spin_lock)
> >   572 |         _compiletime_assert(condition, msg,
> > __compiletime_assert_, __COUNTER__)
> >       |                                             ^
> > include/linux/compiler_types.h:553:25: note: in definition of macro
> > ‘__compiletime_assert’
> >   553 |                         prefix ## suffix();
> >          \
> >       |                         ^~~~~~
> > include/linux/compiler_types.h:572:9: note: in expansion of macro
> > ‘_compiletime_assert’
> >   572 |         _compiletime_assert(condition, msg,
> > __compiletime_assert_, __COUNTER__)
> >       |         ^~~~~~~~~~~~~~~~~~~
> > include/linux/build_bug.h:39:37: note: in expansion of macro
> > ‘compiletime_assert’
> >    39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> >       |                                     ^~~~~~~~~~~~~~~~~~
> > include/linux/build_bug.h:50:9: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
> >    50 |         BUILD_BUG_ON_MSG(condition, "BUILD_BUG_ON failed: " #condition)
> >       |         ^~~~~~~~~~~~~~~~
> > kernel/bpf/rqspinlock.c:695:9: note: in expansion of macro ‘BUILD_BUG_ON’
> >   695 |         BUILD_BUG_ON(__alignof__(rqspinlock_t) !=
> > __alignof__(struct bpf_res_spin_lock));
> >       |         ^~~~~~~~~~~~
> >
> > I haven't investigated it yet.
>
> Yes, I noticed that also, after I started building with defconfigs.
> I pushed a new patch to my github repo.
>
> https://github.com/fthain/linux/tree/atomic_t

Thanks, the updated version fixes the issue.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds