Re: ABI mismatch build error for 6.17.y and rustc 1.91.0

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Nov 04, 2025 at 08:07:13AM +0100, Dirk Behme wrote:
> On 04/11/2025 06:27, Greg KH wrote:
> > My laptop just upgraded rustc to 1.91.0 and now I get the following
> > build error in 6.17.y when doing a 'allmodconfig' build:
> > 
> >    RUSTDOC TK rust/kernel/lib.rs
> > error: mixing `-Zsanitizer` will cause an ABI mismatch in crate `kernel`
> >   --> rust/kernel/lib.rs:3:1
> >    |
> > 3 | //! The `kernel` crate.
> >    | ^
> >    |
> >    = help: the `-Zsanitizer` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely
> >    = note: unset `-Zsanitizer` in this crate is incompatible with `-Zsanitizer=kernel-address` in dependency `core`
> >    = help: set `-Zsanitizer=kernel-address` in this crate or unset `-Zsanitizer` in `core`
> >    = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=sanitizer` to silence this error
> > 
> > I don't see that on Linus's branch, but maybe I don't have the same
> > build options enabled there.  Is 6.17.y missing a patch that is in
> > 6.18-rc to resolve this that I just can't seem to find?
> 
> This one
> 
> https://github.com/Rust-for-Linux/linux/commit/16c43a56b79e2c3220b043236369a129d508c65a

That is not a valid git id in linux-next :(

> https://lore.kernel.org/rust-for-linux/CANiq72=0JJz5XDHGpiyQBd9AmPCr4veJ=2oJywyyqQB8iMxqvA@mail.gmail.com/

Ok, but why am I not seeing this on 6.18-rc?

thanks,

greg k-h