Re: [PATCH] rust: print: add SAFETY comments to unsafe blocks

[Albab Hasan]

Thanks for pointing these out Miguel. I wasn't aware of the prior
patches. Sorry for the
duplicate. Happy to drop mine in favor of whichever version you prefer.

Thanks,
Albab

On Sun, 22 Mar 2026 at 05:14, Miguel Ojeda
<miguel.ojeda.sandonis@xxxxxxxxx> wrote:
>
> On Sat, Mar 21, 2026 at 3:34 PM Albab Hasan <albabhasan276@xxxxxxxxx> wrote:
> >
> > Replace the placeholder // SAFETY: TODO. comments with proper safety
> > descriptions for the two unsafe blocks in rust_fmt_argument and
> > call_printk.
> >
> > For rust_fmt_argument the ptr parameter is provided by the %pA
> > format specifier handler in vsprintf that guarantees it points to a
> > valid properly aligned fmt::Arguments<'_> value. since
> > fmt::Arguments implements Copy the dereference is a bitwise
> > copy with no side effects.
> >
> > For call_printk the safety depends on the functions documented
> > preconditions the format string is one of the fixed compile time
> > constants from format_strings and the module name is null terminated.
> > the arguments match the format specifiers (%s for module name %pA
> > for the fmt::Arguments pointer).
> >
> > Signed-off-by: Albab Hasan <albabhasan276@xxxxxxxxx>
>
> Did you see the following ones?
>
>   https://lore.kernel.org/rust-for-linux/20260212125427.122362-1-alizainuimx@xxxxxxxxx/
>   https://lore.kernel.org/rust-for-linux/20260211182755.82220-1-shivendra02467@xxxxxxxxx/
>
> What is the relation with them? (Cc'ing their authors)
>
> Thanks!
>
> Link: https://github.com/Rust-for-Linux/linux/issues/351
>
> Cheers,
> Miguel