linux.git/rust/Makefile, branch v6.18.21

rust: kbuild: pass `-Zunstable-options` for Rust 1.95.0

2026-03-04T12:21:26+00:00

[ Upstream commit 0a9be83e57de0d0ca8ca4ec610bc344f17a8e5e7 ]

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 
Cc: Wesley Wiser 
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]
Reviewed-by: Gary Guo 
Tested-by: Gary Guo 
Link: https://patch.msgid.link/20260206204535.39431-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda 
Signed-off-by: Sasha Levin

rust: Add -fno-isolate-erroneous-paths-dereference to bindgen_skip_c_flags

2025-11-10T00:37:06+00:00

It's used to work around an objtool issue since commit abb2a5572264
("LoongArch: Add cflag -fno-isolate-erroneous-paths-dereference"), but
it's then passed to bindgen and cause an error because Clang does not
have this option.

Fixes: abb2a5572264 ("LoongArch: Add cflag -fno-isolate-erroneous-paths-dereference")
Acked-by: Miguel Ojeda 
Tested-by: Mingcong Bai 
Signed-off-by: Xi Ruoyao 
Signed-off-by: Huacai Chen

rust: kbuild: workaround `rustdoc` doctests modifier bug

2025-11-03T23:00:06+00:00

The `rustdoc` modifiers bug [1] was fixed in Rust 1.90.0 [2], for which
we added a workaround in commit abbf9a449441 ("rust: workaround `rustdoc`
target modifiers bug").

However, `rustdoc`'s doctest generation still has a similar issue [3],
being fixed at [4], which does not affect us because we apply the
workaround to both, and now, starting with Rust 1.91.0 (released
2025-10-30), `-Zsanitizer` is a target modifier too [5], which means we
fail with:

      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

A simple way around is to add the sanitizer to the list in the existing
workaround (especially if we had not started to pass the sanitizer
flags in the previous commit, since in that case that would not be
necessary). However, that still applies the workaround in more cases
than necessary.

Instead, only modify the doctests flags to ignore the check for
sanitizers, so that it is more local (and thus the compiler keeps checking
it for us in the normal `rustdoc` calls). Since the previous commit
already treated the `rustdoc` calls as kernel objects, this should allow
us in the future to easily remove this workaround when the time comes.

By the way, the `-Cunsafe-allow-abi-mismatch` flag overwrites previous
ones rather than appending, so it needs to be all done in the same flag.
Moreover, unknown modifiers are rejected, and thus we have to gate based
on the version too.

Finally, `-Zsanitizer-cfi-normalize-integers` is not affected (in Rust
1.91.0), so it is not needed in the workaround for the moment.

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/issues/144521 [1]
Link: https://github.com/rust-lang/rust/pull/144523 [2]
Link: https://github.com/rust-lang/rust/issues/146465 [3]
Link: https://github.com/rust-lang/rust/pull/148068 [4]
Link: https://github.com/rust-lang/rust/pull/138736 [5]
Reviewed-by: Alice Ryhl 
Tested-by: Justin M. Forbes 
Link: https://patch.msgid.link/20251102212853.1505384-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda

rust: kbuild: treat `build_error` and `rustdoc` as kernel objects

2025-11-03T23:00:03+00:00

Even if normally `build_error` isn't a kernel object, it should still
be treated as such so that we pass the same flags. Similarly, `rustdoc`
targets are never kernel objects, but we need to treat them as such.

Otherwise, starting with Rust 1.91.0 (released 2025-10-30), `rustc`
will complain about missing sanitizer flags since `-Zsanitizer` is a
target modifier too [1]:

    error: mixing `-Zsanitizer` will cause an ABI mismatch in crate `build_error`
     --> rust/build_error.rs:3:1
      |
    3 | //! Build-time error.
      | ^
      |
      = 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

Thus explicitly mark them as kernel objects.

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/138736 [1]
Reviewed-by: Alice Ryhl 
Tested-by: Justin M. Forbes 
Link: https://patch.msgid.link/20251102212853.1505384-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda

rust: add `pin-init` as a dependency to `bindings` and `uapi`

2025-09-08T11:42:39+00:00

This allows `bindings` and `uapi` to implement `Zeroable` and use other
items from pin-init.

Co-developed-by: Miguel Ojeda 
Signed-off-by: Miguel Ojeda 
Link: https://rust-for-linux.zulipchat.com/#narrow/channel/291565-Help/topic/Zeroable.20trait.20for.20C.20structs/near/510264158
Signed-off-by: Benno Lossin 
Reviewed-by: Alice Ryhl 
Signed-off-by: Miguel Ojeda

rust: warn if `srctree/` links do not exist

2025-09-07T22:11:19+00:00

`srctree/` links may point to nonexistent files, e.g. due to renames
that missed to update the files or simply because of typos.

Since they can be easily checked for validity, do so and print a warning
in the file does not exist.

This found the following cases already in-tree:

    warning: srctree/ link to include/linux/blk_mq.h does not exist
    warning: srctree/ link to include/linux/drm/drm_gem.h does not exist
    warning: srctree/ link to include/linux/drm/drm_drv.h does not exist
    warning: srctree/ link to include/linux/drm/drm_ioctl.h does not exist
    warning: srctree/ link to include/linux/drm/drm_file.h does not exist
    warning: srctree/ link to include/linux/drm/drm_device.h does not exist

Inspired-by: Onur Özkan 
Link: https://lore.kernel.org/rust-for-linux/CANiq72=xCYA7z7_rxpzzKkkhJs6m7L_xEaLMuArVn3ZAcyeHdA@mail.gmail.com/
Reviewed-by: Onur Özkan 
Reviewed-by: Daniel Almeida 
Tested-by: Daniel Almeida 
Signed-off-by: Miguel Ojeda

Merge tag 'alloc-next-v6.18-2025-09-04' of https://github.com/Rust-for-Linux/linux into rust-next

2025-09-07T22:09:41+00:00

Pull alloc and DMA updates from Danilo Krummrich:

  Allocator:
   - Provide information about the minimum alignment guarantees of
     'Kmalloc', 'Vmalloc' and 'KVmalloc'.
   - Take minimum alignment guarantees of allocators for
     'ForeignOwnable' into account.
   - Remove the 'allocator_test' incl. 'Cmalloc'.

  Box:
   - Implement 'Box::pin_slice()', which constructs a pinned slice of
     elements.

  Vec:
   - Simplify KUnit test module name to 'rust_kvec'.
   - Add doc-test for 'Vec::as_slice()'.
   - Constify various methods.

  DMA:
   - Update 'ARef' and 'AlwaysRefCounted' imports.

  MISC:
   - Remove support for unused host '#[test]'s.
   - Constify 'ArrayLayout::new_unchecked()'.

* tag 'alloc-next-v6.18-2025-09-04' of https://github.com/Rust-for-Linux/linux:
  rust: alloc: remove `allocator_test`
  rust: kernel: remove support for unused host `#[test]`s
  rust: alloc: implement Box::pin_slice()
  rust: alloc: add ARCH_KMALLOC_MINALIGN to bindgen blocklist
  rust: dma: Update ARef and AlwaysRefCounted imports from sync::aref
  rust: alloc: take the allocator into account for FOREIGN_ALIGN
  rust: alloc: specify the minimum alignment of each allocator
  rust: make `kvec::Vec` functions `const fn`
  rust: make `ArrayLayout::new_unchecked` a `const fn`
  rust: alloc: kvec: simplify KUnit test module name to "rust_kvec"
  rust: alloc: kvec: add doc example for as_slice method

rust: kernel: remove support for unused host `#[test]`s

2025-08-24T13:29:51+00:00

Since commit 028df914e546 ("rust: str: convert `rusttest` tests into
KUnit"), we do not have anymore host `#[test]`s that run in the host.

Moreover, we do not plan to add any new ones -- tests should generally
run within KUnit, since there they are built the same way the kernel
does. While we may want to have some way to define tests that can also
be run outside the kernel, we still want to test within the kernel too
[1], and thus would likely use a custom syntax anyway to define them.

Thus simplify the `rusttest` target by removing support for host
`#[test]`s for the `kernel` crate.

This still maintains the support for the `macros` crate, even though we
do not have any such tests there.

Link: https://lore.kernel.org/rust-for-linux/CABVgOS=AKHSfifp0S68K3jgNZAkALBr=7iFb=niryG5WDxjSrg@mail.gmail.com/ [1]
Signed-off-by: Miguel Ojeda 
Reviewed-by: Danilo Krummrich 
Reviewed-by: David Gow 
Link: https://lore.kernel.org/r/20250726180750.2735836-1-ojeda@kernel.org
Signed-off-by: Danilo Krummrich

rust: kbuild: clean output before running `rustdoc`

2025-08-12T19:10:50+00:00

`rustdoc` can get confused when generating documentation into a folder
that contains generated files from other `rustdoc` versions.

For instance, running something like:

    rustup default 1.78.0
    make LLVM=1 rustdoc
    rustup default 1.88.0
    make LLVM=1 rustdoc

may generate errors like:

    error: couldn't generate documentation: invalid template: last line expected to start with a comment
      |
      = note: failed to create or modify "./Documentation/output/rust/rustdoc/src-files.js"

Thus just always clean the output folder before generating the
documentation -- we are anyway regenerating it every time the `rustdoc`
target gets called, at least for the time being.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Reported-by: Daniel Almeida 
Closes: https://rust-for-linux.zulipchat.com/#narrow/channel/288089/topic/x/near/527201113
Reviewed-by: Tamir Duberstein 
Link: https://lore.kernel.org/r/20250726133435.2460085-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda

rust: workaround `rustdoc` target modifiers bug

2025-08-12T19:06:48+00:00

Starting with Rust 1.88.0 (released 2025-06-26), `rustdoc` complains
about a target modifier mismatch in configurations where `-Zfixed-x18`
is passed:

    error: mixing `-Zfixed-x18` will cause an ABI mismatch in crate `rust_out`
      |
      = help: the `-Zfixed-x18` flag modifies the ABI so Rust crates compiled with different values of this flag cannot be used together safely
      = note: unset `-Zfixed-x18` in this crate is incompatible with `-Zfixed-x18=` in dependency `core`
      = help: set `-Zfixed-x18=` in this crate or unset `-Zfixed-x18` in `core`
      = help: if you are sure this will not cause problems, you may use `-Cunsafe-allow-abi-mismatch=fixed-x18` to silence this error

The reason is that `rustdoc` was not passing the target modifiers when
configuring the session options, and thus it would report a mismatch
that did not exist as soon as a target modifier is used in a dependency.

We did not notice it in the kernel until now because `-Zfixed-x18` has
been a target modifier only since 1.88.0 (and it is the only one we use
so far).

The issue has been reported upstream [1] and a fix has been submitted
[2], including a test similar to the kernel case.

  [ This is now fixed upstream (thanks Guillaume for the quick review),
    so it will be fixed in Rust 1.90.0 (expected 2025-09-18).

      - Miguel ]

Meanwhile, conditionally pass `-Cunsafe-allow-abi-mismatch=fixed-x18`
to workaround the issue on our side.

Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Reported-by: Konrad Dybcio 
Closes: https://lore.kernel.org/rust-for-linux/36cdc798-524f-4910-8b77-d7b9fac08d77@oss.qualcomm.com/
Link: https://github.com/rust-lang/rust/issues/144521 [1]
Link: https://github.com/rust-lang/rust/pull/144523 [2]
Reviewed-by: Alice Ryhl 
Link: https://lore.kernel.org/r/20250727092317.2930617-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda