Re: [PATCH] rust: fmt: fix {:p} formatting for raw pointers

[Alice Ryhl <aliceryhl@google.com>]

On Thu, Dec 18, 2025 at 11:27:09AM +0800, Ke Sun wrote:
> The fmt! macro wraps arguments as Adapter(&arg), causing raw pointers
> to be wrapped as Adapter(&*mut T). The generic Pointer implementation
> then formats the reference address (stack address of the variable)
> instead of the pointer value.
> 
> Add specialized Pointer implementations for Adapter<&*mut T> and
> Adapter<&*const T> that dereference before formatting.
> 
> Example:
>     let ptr: *mut SomeStruct = 0x12345678 as *mut _;
>     dev_info!(dev, "ptr: {:p}", ptr);
> 
> Before (wrong): prints stack address of `ptr` variable, e.g. 0xffffc90001234560
> After (correct): prints pointer value, e.g. 0x12345678
> 
> Signed-off-by: Ke Sun <sunke@kylinos.cn>

Ahh ... the goal here is that trying to print a raw pointer should not
compile at all. It's unfortunate if that's not what actually happens.

Alice