Re: [PATCH][next] fsnotify: Avoid -Wflex-array-member-not-at-end warning

[Gustavo A. R. Silva]

On 3/6/24 01:36, Amir Goldstein wrote:
> On Wed, Mar 6, 2024 at 1:52 AM Kees Cook <keescook@xxxxxxxxxxxx> wrote:
> > On Tue, Mar 05, 2024 at 04:18:46PM -0600, Gustavo A. R. Silva wrote:
> > > -Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
> > > ready to enable it globally.
> > >
> > > There is currently a local structure `f` that is using a flexible
> > > `struct file_handle` as header for an on-stack place-holder for the
> > > flexible-array member `unsigned char f_handle[];`.
> > >
> > > struct {
> > >        struct file_handle handle;
> > >        u8 pad[MAX_HANDLE_SZ];
> > > } f;
> >
> > This code pattern is "put a flex array struct on the stack", but we have
> > a macro for this now:
> >
> > DEFINE_FLEX(struct file_handle, handle, f_handle, MAX_HANDLE_SZ);
> >
> > And you can even include the initializer:
> >
> > _DEFINE_FLEX(struct file_handle, handle, f_handle, MAX_HANDLE_SZ,
> >               = { .handle_bytes = MAX_HANDLE_SZ });
>
> Indeed that looks much nicer.


Yeah, I'll probably wait for this to land before I send a v2:

https://lore.kernel.org/linux-hardening/20240306010746.work.678-kees@xxxxxxxxxx/

Thanks
--
Gustavo