Re: [PATCH v4 2/2] rust: uaccess: refactor to use `overflow_assert!`

[Tamir Duberstein <tamird@gmail.com>]

On Sat, Jun 28, 2025 at 10:44 PM Antonio Hickey
<contact@antoniohickey.com> wrote:
>
> Using the `overflow_assert!` macro here adds documentation to
> the intent of the assertion, and avoids local `#ifdefs`s by
> encapsulating the conditional behavior to the macro itself.
>
> Co-developed-by: Daniel Cote <danielstonecote@gmail.com>
> Signed-off-by: Daniel Cote <danielstonecote@gmail.com>
> Signed-off-by: Antonio Hickey <contact@antoniohickey.com>
> Link: https://github.com/Rust-for-Linux/linux/issues/1159
> Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> ---

Reviewed-by: Tamir Duberstein <tamird@gmail.com>

>  rust/kernel/uaccess.rs | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/rust/kernel/uaccess.rs b/rust/kernel/uaccess.rs
> index 635a03e0989f..452a5e0d76d2 100644
> --- a/rust/kernel/uaccess.rs
> +++ b/rust/kernel/uaccess.rs
> @@ -9,6 +9,7 @@
>      bindings,
>      error::Result,
>      ffi::{c_char, c_void},
> +    overflow_assert,
>      prelude::*,
>      transmute::{AsBytes, FromBytes},
>  };
> @@ -394,8 +395,7 @@ fn raw_strncpy_from_user(dst: &mut [MaybeUninit<u8>], src: UserPtr) -> Result<us
>          return Err(Error::from_errno(res as i32));
>      }
>
> -    #[cfg(CONFIG_RUST_OVERFLOW_CHECKS)]
> -    assert!(res <= len);
> +    overflow_assert!(res <= len);
>
>      // GUARANTEES: `strncpy_from_user` was successful, so `dst` has contents in accordance with the
>      // guarantees of this function.
> --
> 2.50.0
>
>
>