Re: [PATCH v3][next] overflow: Fix direct struct member initialization in _DEFINE_FLEX()

[Kees Cook <kees@kernel.org>]

On Fri, May 30, 2025 at 11:06:01AM -0700, Kees Cook wrote:
> #define __DEFINE_FLEX(type, name, member, count, trailer...)		\
>         _Static_assert(__builtin_constant_p(count),			\
>                        "onstack flex array members require compile-time const count"); \
>         union {								\
>                 u8 bytes[struct_size_t(type, member, count)];		\
>                 type obj;						\
>         } name##_u trailer;						\
>         type *name = (type *)&name##_u
> 
> #define _DEFINE_FLEX(type, name, member, count, initializer...)		\
> 	__DEFINE_FLEX(type, name, member, count, = { .obj = initializer })
> [...]
> Does that look like what you'd want? (Note I didn't actually build this;
> I want to make sure the concept is workable...)

FWIW, this is working as expected: https://godbolt.org/z/P7Go8Tr33

I'll send a proper patch...

-- 
Kees Cook