Re: [PATCH] rust: kbuild: pass `-Zunstable-options` for Rust 1.95.0

["Gary Guo" <gary@garyguo.net>]

On Fri Feb 6, 2026 at 8:45 PM GMT, Miguel Ojeda wrote:
> Custom target specifications are unstable, but starting with Rust 1.95.0,
> `rustc` requires to explicitly pass `-Zunstable-options` to use them [1]:
> 
>     error: error loading target specification: custom targets are unstable and require `-Zunstable-options`
>       |
>       = help: run `rustc --print target-list` for a list of built-in targets
> 
> David (Rust compiler team lead), writes:
> 
>    "We're destabilising custom targets to allow us to move forward with
>     build-std without accidentally exposing functionality that we'd like
>     to revisit prior to committing to. I'll start a thread on Zulip to
>     discuss with the RfL team how we can come up with an alternative
>     for them."
> 
> Thus pass it.
> 
> Cc: David Wood <david@davidtw.co>
> Cc: Wesley Wiser <wwiser@gmail.com>
> Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
> Link: https://github.com/rust-lang/rust/pull/151534 [1]
> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

I can confirm that build will fail on x64 without this patch in latest nightly
and this fixed it.

Reviewed-by: Gary Guo <gary@garyguo.net>
Tested-by: Gary Guo <gary@garyguo.net>

> ---
>  rust/Makefile | 3 +++
>  1 file changed, 3 insertions(+)