Re: [PATCH 1/3] rust: allocator: Prevent mis-aligned allocation

[Boqun Feng]

On Sun, Jul 30, 2023 at 10:41:54PM +0000, Björn Roy Baron wrote:
> On Jul 30, 2023, 10:43 PM, Miguel Ojeda < miguel.ojeda.sandonis@xxxxxxxxx> wrote:
> > On Sun, Jul 30, 2023 at 3:29 AM Boqun > Feng <boqun.feng@xxxxxxxxx> wrote:
> > >
> > > +// Note: Although these are *safe* functions, but they are only generated at
> > > +// `GlobalAlloc` callsites, hence we assume the parameters obey the same
> > > +// `GlobalAlloc` function safety requirements: size and align should form a
> > > +// valid layout, and size is greater than 0.
> >
> > Thanks for adding all the `// SAFETY` comments here Boqun!
> >
> > Björn, do they look good to you? (since you fixed the issue in the compiler)
> 
> Based on a quick look, yes. The __rust_* methods that are normally generated by the compiled directly jump to the respective global allocator method, so they have the same safety requirements.
> 

Good to know, thanks!

> >
> > On this comment in particular, "generated at `GlobalAlloc` callsites"
> sounds a bit confusing to me. Would "... called by the compiler with
> parameters that obey ..." make sense? Or does the sentence refer to

Agreed. It's better. So reword as below:

// Note: Although these are *safe* functions, but they are called by the
// compiler with the parameters that obey the same `GlobalAlloc`
// function safety requirements: size and align should form a valid
// layout, and size is greater than 0.

Regards,
Boqun

> the normal case (i.e. when the functions are generated)? Anyway, it is
> not a big deal.
> >
> > Cheers,
> > Miguel
> 
> Cheers,
> Björn
> 
> (resent as I accidentally sent html instead of plain text)