As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
we are going to follow Debian Stable's Rust versions as our minimum
supported version.

Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
still uses to this day [3] (i.e. no update to Rust 1.85.1).

Debian Trixie was released with `bindgen` 0.71.1, which it also still
uses to this day [4].

Debian Trixie's release happened on 2025-08-09 [5], which means that a
fair amount of time has passed since its release for kernel developers
to upgrade.

Thus bump the minimum to the new versions, i.e.

  - Rust: 1.78.0 -> 1.85.0
  - bindgen: 0.65.1 -> 0.71.1

There are a few main parts to the series, in this order:

  - A few cleanups that can be performed before the bumps.
  - The Rust bump (and its cleanups).
  - The `bindgen` bump (and its cleanups).
  - Documentation updates.
  - The `cfi_encoding` patch, added here, which needs the bump.
  - The per-version flags support and a Clippy cleanup on top.

Link: https://lwn.net/Articles/1050174/ [1]
Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
Link: https://packages.debian.org/trixie/rustc [3]
Link: https://packages.debian.org/trixie/bindgen [4]
Link: https://www.debian.org/releases/trixie/ [5]
---
v1: https://lore.kernel.org/rust-for-linux/20260401114540.30108-1-ojeda@kernel.org/
v2:
  - Added patch to globally allow `incompatible_msrv` and removed the
    last instance.

  - Replaced `--remap-path-prefix` patches with one that drops the
    workaround entirely (and place it as the first one) and summarizes
    the discussion.

    I also noticed that `--remap-path-prefix` for `rustdoc` is still
    unstable (unlike `rustc`'s one), so I added it to our list as usual
    (https://github.com/Rust-for-Linux/linux/issues/2). There does not
    seem to be a tracking issue, so I asked upstream about it.

    We will need these two lines as the resolution for the conflict:

        $(RUSTDOC) $(filter-out $(skip_flags) --remap-path-scope=%,$(if $(rustdoc_host),$(rust_common_flags),$(rust_flags))) \

        $(RUSTDOC) --test $(filter-out --remap-path-scope=%,$(rust_flags)) \

  - Reworked the `extract_if` patch to use it (unstably). The feature
    last major change happened in Rust 1.85.0, so that is fine.

  - Moved `$(HOSTRUSTFLAGS)` below so that per-version flags (like
    lints) can be overridden too. Please see the details in the commit
    and my reply to v1.

  - Added `feature(extract_if)` and `feature(non_null_convenience)`
    items to https://github.com/Rust-for-Linux/linux/issues/1223.

    Then reworded the commits accordingly to include the references
    to tracking issues and PRs.

  - Other rewords, e.g. the "beyond" typo.

  - Rebased on top of `rust-next`.

  - Picked up tags.

Alice Ryhl (1):
  rust: declare cfi_encoding for lru_status

Miguel Ojeda (32):
  rust: kbuild: remove `--remap-path-prefix` workarounds
  rust: kbuild: remove "`try` keyword" workaround for `bindgen` < 0.59.2
  rust: kbuild: remove unneeded old `allow`s for generated layout tests
  gpu: nova-core: bindings: remove unneeded `cfg_attr`
  rust: bump Rust minimum supported version to 1.85.0 (Debian Trixie)
  rust: bump Clippy's MSRV and clean `incompatible_msrv` allows
  rust: allow globally `clippy::incompatible_msrv`
  rust: simplify `RUSTC_VERSION` Kconfig conditions
  rust: remove `RUSTC_HAS_SLICE_AS_FLATTENED` and simplify code
  rust: remove `RUSTC_HAS_COERCE_POINTEE` and simplify code
  rust: kbuild: remove skipping of `-Wrustdoc::unescaped_backticks`
  rust: kbuild: remove `feature(...)`s that are now stable
  rust: transmute: simplify code with Rust 1.80.0 `split_at_*checked()`
  rust: alloc: simplify with `NonNull::add()` now that it is stable
  rust: macros: simplify code using `feature(extract_if)`
  rust: block: update `const_refs_to_static` MSRV TODO comment
  rust: bump `bindgen` minimum supported version to 0.71.1 (Debian
    Trixie)
  rust: rust_is_available: remove warning for `bindgen` 0.66.[01]
  rust: rust_is_available: remove warning for `bindgen` < 0.69.5 &&
    libclang >= 19.1
  rust: kbuild: update `bindgen --rust-target` version and replace
    comment
  rust: kbuild: remove "dummy parameter" workaround for `bindgen` <
    0.71.1
  docs: rust: quick-start: openSUSE provides `rust-src` package nowadays
  docs: rust: quick-start: update Ubuntu versioned packages
  docs: rust: quick-start: update minimum Ubuntu version
  docs: rust: quick-start: add Ubuntu 26.04 LTS and remove subsection
    title
  docs: rust: quick-start: remove Gentoo "testing" note
  docs: rust: quick-start: remove Nix "unstable channel" note
  docs: rust: quick-start: remove GDB/Binutils mention
  docs: rust: general-information: simplify Kconfig example
  docs: rust: general-information: use real example
  rust: kbuild: support global per-version flags
  rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0

 .clippy.toml                                  |  2 +-
 Documentation/process/changes.rst             |  4 +-
 Documentation/rust/general-information.rst    |  4 +-
 Documentation/rust/quick-start.rst            | 52 +++++++----------
 Makefile                                      | 12 +++-
 arch/Kconfig                                  |  3 +-
 arch/arm64/Kconfig                            |  8 ---
 arch/riscv/Kconfig                            |  3 -
 drivers/android/binder/Makefile               |  3 +-
 drivers/android/binder/page_range.rs          |  6 +-
 drivers/android/binder/page_range_helper.c    | 24 --------
 drivers/android/binder/page_range_helper.h    | 15 -----
 drivers/gpu/nova-core/gsp/cmdq.rs             |  6 +-
 drivers/gpu/nova-core/gsp/fw/r570_144.rs      |  3 -
 init/Kconfig                                  | 15 +----
 rust/Makefile                                 | 31 ++--------
 rust/bindgen_parameters                       |  8 +--
 rust/bindings/bindings_helper.h               |  1 -
 rust/bindings/lib.rs                          |  5 +-
 rust/kernel/alloc/allocator/iter.rs           |  8 +--
 rust/kernel/alloc/kbox.rs                     | 29 +---------
 rust/kernel/block/mq/gen_disk.rs              |  4 +-
 rust/kernel/lib.rs                            | 30 +---------
 rust/kernel/list/arc.rs                       | 22 +------
 rust/kernel/prelude.rs                        |  3 -
 rust/kernel/ptr.rs                            |  1 -
 rust/kernel/slice.rs                          | 49 ----------------
 rust/kernel/sync/arc.rs                       | 21 +------
 rust/kernel/transmute.rs                      | 35 ++---------
 rust/macros/helpers.rs                        |  1 -
 rust/macros/kunit.rs                          |  9 +--
 rust/macros/lib.rs                            |  3 +
 rust/uapi/lib.rs                              |  5 +-
 scripts/Makefile.build                        |  6 +-
 scripts/min-tool-version.sh                   |  4 +-
 scripts/rust_is_available.sh                  | 36 +-----------
 scripts/rust_is_available_bindgen_0_66.h      |  2 -
 ...ust_is_available_bindgen_libclang_concat.h |  3 -
 scripts/rust_is_available_test.py             | 58 +------------------
 39 files changed, 83 insertions(+), 451 deletions(-)
 delete mode 100644 drivers/android/binder/page_range_helper.c
 delete mode 100644 drivers/android/binder/page_range_helper.h
 delete mode 100644 rust/kernel/slice.rs
 delete mode 100644 scripts/rust_is_available_bindgen_0_66.h
 delete mode 100644 scripts/rust_is_available_bindgen_libclang_concat.h


base-commit: 36f5a2b09e650b82d7b2a106e3b93af48c2010d9
--
2.53.0

On Mon, Apr 6, 2026 at 1:53 AM Miguel Ojeda <ojeda@kernel.org> wrote:
>
> As proposed in the past in e.g. LPC 2025 and the Maintainers Summit [1],
> we are going to follow Debian Stable's Rust versions as our minimum
> supported version.
>
> Debian Trixie was released with a Rust 1.85.0 toolchain [2], which it
> still uses to this day [3] (i.e. no update to Rust 1.85.1).
>
> Debian Trixie was released with `bindgen` 0.71.1, which it also still
> uses to this day [4].
>
> Debian Trixie's release happened on 2025-08-09 [5], which means that a
> fair amount of time has passed since its release for kernel developers
> to upgrade.
>
> Thus bump the minimum to the new versions, i.e.
>
>   - Rust: 1.78.0 -> 1.85.0
>   - bindgen: 0.65.1 -> 0.71.1
>
> There are a few main parts to the series, in this order:
>
>   - A few cleanups that can be performed before the bumps.
>   - The Rust bump (and its cleanups).
>   - The `bindgen` bump (and its cleanups).
>   - Documentation updates.
>   - The `cfi_encoding` patch, added here, which needs the bump.
>   - The per-version flags support and a Clippy cleanup on top.
>
> Link: https://lwn.net/Articles/1050174/ [1]
> Link: https://www.debian.org/releases/trixie/release-notes/whats-new.en.html#desktops-and-well-known-packages [2]
> Link: https://packages.debian.org/trixie/rustc [3]
> Link: https://packages.debian.org/trixie/bindgen [4]
> Link: https://www.debian.org/releases/trixie/ [5]

Applied series to `rust-next` -- thanks everyone!

Let's see if we find any issue in -next.

(If someone wants to give tags today, then I am happy to pick them up)

Cheers,
Miguel

On 4/6/26 2:03 AM, Miguel Ojeda wrote:
> On Mon, Apr 6, 2026 at 1:53 AM Miguel Ojeda <ojeda@kernel.org> wrote:
... 
> Applied series to `rust-next` -- thanks everyone!
> 
> Let's see if we find any issue in -next.
> 

Looks good from the perspective of this patchset. I am seeing
one remaining problem that we previously came up with a fix for,
so I expect that that fix is staged in another branch. But in
case it's not, here is the report:

On today's rust-next, using rustc 1.85.0, at commit 232e79c72f57
("rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0"):

  CLIPPY [M] drivers/gpu/drm/nova/nova.o
warning: consider removing unnecessary double parentheses
    --> rust/doctests_kernel_generated.rs:4240:14
     |
4240 |     pr_info!("The policy details are: {:?}\n", (policy.cpu(), policy.cur()));
     |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#double_parens
     = note: `-W clippy::double-parens` implied by `-W clippy::all`
     = help: to override `-W clippy::all` add `#[allow(clippy::double_parens)]`

warning: 1 warning emitted



thanks,
-- 
John Hubbard

On Mon, Apr 6, 2026 at 8:51 PM John Hubbard <jhubbard@nvidia.com> wrote:
>
> Looks good from the perspective of this patchset. I am seeing
> one remaining problem that we previously came up with a fix for,
> so I expect that that fix is staged in another branch. But in
> case it's not, here is the report:
>
> On today's rust-next, using rustc 1.85.0, at commit 232e79c72f57
> ("rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0"):
>
>   CLIPPY [M] drivers/gpu/drm/nova/nova.o
> warning: consider removing unnecessary double parentheses
>     --> rust/doctests_kernel_generated.rs:4240:14
>      |
> 4240 |     pr_info!("The policy details are: {:?}\n", (policy.cpu(), policy.cur()));
>      |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>      |
>      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#double_parens
>      = note: `-W clippy::double-parens` implied by `-W clippy::all`
>      = help: to override `-W clippy::all` add `#[allow(clippy::double_parens)]`
>
> warning: 1 warning emitted

That is already fixed and in mainline: 487f9b3dc6e5 ("rust: cpufreq:
suppress clippy::double_parens in Policy doctest").

Cheers,
Miguel

On 4/6/26 12:01 PM, Miguel Ojeda wrote:
> On Mon, Apr 6, 2026 at 8:51 PM John Hubbard <jhubbard@nvidia.com> wrote:
>>
>> Looks good from the perspective of this patchset. I am seeing
>> one remaining problem that we previously came up with a fix for,
>> so I expect that that fix is staged in another branch. But in
>> case it's not, here is the report:
>>
>> On today's rust-next, using rustc 1.85.0, at commit 232e79c72f57
>> ("rust: kbuild: allow `clippy::precedence` for Rust < 1.86.0"):
>>
>>   CLIPPY [M] drivers/gpu/drm/nova/nova.o
>> warning: consider removing unnecessary double parentheses
>>     --> rust/doctests_kernel_generated.rs:4240:14
>>      |
>> 4240 |     pr_info!("The policy details are: {:?}\n", (policy.cpu(), policy.cur()));
>>      |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>      |
>>      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#double_parens
>>      = note: `-W clippy::double-parens` implied by `-W clippy::all`
>>      = help: to override `-W clippy::all` add `#[allow(clippy::double_parens)]`
>>
>> warning: 1 warning emitted
> 
> That is already fixed and in mainline: 487f9b3dc6e5 ("rust: cpufreq:
> suppress clippy::double_parens in Policy doctest").
> 

That's what I thought I recalled, too. Weird that it is not in rust-next
already, though.


thanks,
-- 
John Hubbard

On Mon, Apr 6, 2026 at 9:07 PM John Hubbard <jhubbard@nvidia.com> wrote:
>
> That's what I thought I recalled, too. Weird that it is not in rust-next
> already, though.

It is normal -- in the kernel back merges are generally to be avoided.

Cheers,
Miguel