linux-next: manual merge of the rust tree with the origin tree

linux-next: manual merge of the rust tree with the origin tree

[Mark Brown]

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Hi all,

Today's linux-next merge of the rust tree got a conflict in:

  rust/kernel/lib.rs

between commits:

  08da98f18f4f9 ("rust: ptr: add `KnownSize` trait to support DST size info extraction")
  f41941aab3acd ("rust: ptr: add projection infrastructure")

from the origin tree and commit:

  7fa2b092b1ff8 ("rust: kbuild: remove `feature(...)`s that are now stable")

from the rust tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --cc rust/kernel/lib.rs
index d93292d47420f,b48221a5b4ec5..0000000000000
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@@ -16,33 -16,9 +16,12 @@@
  // Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on
  // the unstable features in use.
  //
- // Stable since Rust 1.79.0.
- #![feature(generic_nonzero)]
- #![feature(inline_const)]
- #![feature(pointer_is_aligned)]
- #![feature(slice_ptr_len)]
- //
- // Stable since Rust 1.80.0.
- #![feature(slice_flatten)]
- //
- // Stable since Rust 1.81.0.
- #![feature(lint_reasons)]
- //
- // Stable since Rust 1.82.0.
- #![feature(raw_ref_op)]
- //
- // Stable since Rust 1.83.0.
- #![feature(const_maybe_uninit_as_mut_ptr)]
- #![feature(const_mut_refs)]
- #![feature(const_option)]
- #![feature(const_ptr_write)]
- #![feature(const_refs_to_cell)]
- //
 +// Stable since Rust 1.84.0.
 +#![feature(strict_provenance)]
 +//
  // Expected to become stable.
  #![feature(arbitrary_self_types)]
+ #![feature(derive_coerce_pointee)]
  //
  // To be determined.
  #![feature(used_with_arg)]

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Re: linux-next: manual merge of the rust tree with the origin tree

[Miguel Ojeda]

On Mon, Apr 6, 2026 at 3:02 PM Mark Brown <broonie@kernel.org> wrote:
>
>  +// Stable since Rust 1.84.0.
>  +#![feature(strict_provenance)]
>  +//

This one can (should) be removed, since it is < 1.85.0 which is the
new minimum (i.e. already by the time that commits happens) -- please
see my resolution at:

  https://lore.kernel.org/linux-next/CANiq72kdxB=W3_CV1U44oOK3SssztPo2wLDZt6LP94TEO+Kj4g@mail.gmail.com/

Thanks Mark!

Cheers,
Miguel

Re: linux-next: manual merge of the rust tree with the origin tree

[Mark Brown]

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On Mon, Apr 06, 2026 at 03:11:57PM +0200, Miguel Ojeda wrote:
> On Mon, Apr 6, 2026 at 3:02 PM Mark Brown <broonie@kernel.org> wrote:
> >
> >  +// Stable since Rust 1.84.0.
> >  +#![feature(strict_provenance)]
> >  +//
> 
> This one can (should) be removed, since it is < 1.85.0 which is the
> new minimum (i.e. already by the time that commits happens) -- please
> see my resolution at:

I'll update that if I get another conflict.

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linux-next: manual merge of the rust tree with the origin tree

[Mark Brown]

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Hi all,

Today's linux-next merge of the rust tree got a conflict in:

  rust/Makefile

between commit:

  dda135077ecc9 ("rust: build: remap path to avoid absolute path")

from the origin tree and commit:

  8980db6e99870 ("rust: kbuild: remove `--remap-path-prefix` workarounds")

from the rust tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --cc rust/Makefile
index 9801af2e1e027,866f9afc1b7f8..0000000000000
--- a/rust/Makefile
+++ b/rust/Makefile
@@@ -144,12 -145,7 +145,7 @@@ doctests_modifiers_workaround := $(rust
  quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
        cmd_rustdoc = \
  	OBJTREE=$(abspath $(objtree)) \
- 	$(RUSTDOC) $(filter-out $(skip_flags) --remap-path-prefix=% --remap-path-scope=%, \
- 			$(if $(rustdoc_host),$(rust_common_flags),$(rust_flags))) \
 -	$(RUSTDOC) $(filter-out $(skip_flags),$(if $(rustdoc_host),$(rust_common_flags),$(rust_flags))) \
++	$(RUSTDOC) $(filter-out $(skip_flags) --remap-path-scope=%,$(if $(rustdoc_host),$(rust_common_flags),$(rust_flags))) \
  		$(rustc_target_flags) -L$(objtree)/$(obj) \
  		-Zunstable-options --generate-link-to-definition \
  		--output $(rustdoc_output) \
@@@ -335,7 -329,7 +329,7 @@@ quiet_cmd_rustdoc_test_kernel = RUSTDO
  	rm -rf $(objtree)/$(obj)/test/doctests/kernel; \
  	mkdir -p $(objtree)/$(obj)/test/doctests/kernel; \
  	OBJTREE=$(abspath $(objtree)) \
- 	$(RUSTDOC) --test $(filter-out --remap-path-prefix=% --remap-path-scope=%,$(rust_flags)) \
 -	$(RUSTDOC) --test $(rust_flags) \
++	$(RUSTDOC) --test $(filter-out --remap-path-scope=%,$(rust_flags)) \
  		-L$(objtree)/$(obj) --extern ffi --extern pin_init \
  		--extern kernel --extern build_error --extern macros \
  		--extern bindings --extern uapi \

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Re: linux-next: manual merge of the rust tree with the origin tree

[Miguel Ojeda]

On Mon, Apr 6, 2026 at 3:13 PM Mark Brown <broonie@kernel.org> wrote:
>
> I fixed it up (see below) and can carry the fix as necessary.

Looks good, thanks!

Cheers,
Miguel

linux-next: manual merge of the rust tree with the origin tree

[Mark Brown]

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Hi all,

Today's linux-next merge of the rust tree got a conflict in:

  scripts/Makefile.build

between commit:

  f41941aab3acd ("rust: ptr: add projection infrastructure")

from the origin tree and commit:

  7fa2b092b1ff8 ("rust: kbuild: remove `feature(...)`s that are now stable")

from the rust tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --cc scripts/Makefile.build
index 3652b85be5459,57cff77c28973..0000000000000
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@@ -310,18 -310,13 +310,14 @@@ $(obj)/%.lst: $(obj)/%.c FORC
  
  # The features in this list are the ones allowed for non-`rust/` code.
  #
- #   - Stable since Rust 1.79.0: `feature(slice_ptr_len)`.
- #   - Stable since Rust 1.81.0: `feature(lint_reasons)`.
- #   - Stable since Rust 1.82.0: `feature(asm_const)`,
- #     `feature(offset_of_nested)`, `feature(raw_ref_op)`.
 +#   - Stable since Rust 1.84.0: `feature(strict_provenance)`.
  #   - Stable since Rust 1.87.0: `feature(asm_goto)`.
  #   - Expected to become stable: `feature(arbitrary_self_types)`.
  #   - To be determined: `feature(used_with_arg)`.
  #
  # Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on
  # the unstable features in use.
- rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,offset_of_nested,raw_ref_op,slice_ptr_len,strict_provenance,used_with_arg
 -rust_allowed_features := arbitrary_self_types,asm_goto,used_with_arg
++rust_allowed_features := arbitrary_self_types,asm_goto,slice_ptr_len,strict_provenance,used_with_arg
  
  # `--out-dir` is required to avoid temporaries being created by `rustc` in the
  # current working directory, which may be not accessible in the out-of-tree

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Re: linux-next: manual merge of the rust tree with the origin tree

[Miguel Ojeda]

On Mon, Apr 6, 2026 at 3:12 PM Mark Brown <broonie@kernel.org> wrote:
>
>  +#   - Stable since Rust 1.84.0: `feature(strict_provenance)`.

Ditto here (please see my other reply).

i.e. one side adds the feature, but the other removes everything < 1.85.0.

> ++rust_allowed_features := arbitrary_self_types,asm_goto,slice_ptr_len,strict_provenance,used_with_arg

And here, i.e. both `slice_ptr_len` and `strict_provenance` are not
needed anymore.

Thanks!

Cheers,
Miguel

linux-next: manual merge of the rust tree with the origin tree

[Mark Brown]

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Hi all,

Today's linux-next merge of the rust tree got a conflict in:

  rust/kernel/ptr.rs

between commit:

  08da98f18f4f9 ("rust: ptr: add `KnownSize` trait to support DST size info extraction")

from the origin tree and commit:

  0a51b384e0dec ("rust: ptr: add const_align_up()")

from the rust tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --cc rust/kernel/ptr.rs
index bdc2d79ff6699,c7788656a1621..0000000000000
--- a/rust/kernel/ptr.rs
+++ b/rust/kernel/ptr.rs
@@@ -2,15 -2,11 +2,17 @@@
  
  //! Types and functions to work with pointers and addresses.
  
 -use core::mem::align_of;
 +pub mod projection;
 +pub use crate::project_pointer as project;
 +
 +use core::mem::{
 +    align_of,
 +    size_of, //
 +};
  use core::num::NonZero;
  
+ use crate::const_assert;
+ 
  /// Type representing an alignment, which is always a power of two.
  ///
  /// It is used to validate that a given value is a valid alignment, and to perform masking and
@@@ -232,24 -226,31 +232,53 @@@ macro_rules! impl_alignable_uint 
  
  impl_alignable_uint!(u8, u16, u32, u64, usize);
  
 +/// Trait to represent compile-time known size information.
 +///
 +/// This is a generalization of [`size_of`] that works for dynamically sized types.
 +pub trait KnownSize {
 +    /// Get the size of an object of this type in bytes, with the metadata of the given pointer.
 +    fn size(p: *const Self) -> usize;
 +}
 +
 +impl<T> KnownSize for T {
 +    #[inline(always)]
 +    fn size(_: *const Self) -> usize {
 +        size_of::<T>()
 +    }
 +}
 +
 +impl<T> KnownSize for [T] {
 +    #[inline(always)]
 +    fn size(p: *const Self) -> usize {
 +        p.len() * size_of::<T>()
 +    }
 +}
++
+ /// Aligns `value` up to `align`.
+ ///
+ /// This is the const-compatible equivalent of [`Alignable::align_up`].
+ ///
+ /// Returns [`None`] on overflow.
+ ///
+ /// # Examples
+ ///
+ /// ```
+ /// use kernel::{
+ ///     ptr::{
+ ///         const_align_up,
+ ///         Alignment, //
+ ///     },
+ ///     sizes::SZ_4K, //
+ /// };
+ ///
+ /// assert_eq!(const_align_up(0x4f, Alignment::new::<16>()), Some(0x50));
+ /// assert_eq!(const_align_up(0x40, Alignment::new::<16>()), Some(0x40));
+ /// assert_eq!(const_align_up(1, Alignment::new::<SZ_4K>()), Some(SZ_4K));
+ /// ```
+ #[inline(always)]
+ pub const fn const_align_up(value: usize, align: Alignment) -> Option<usize> {
+     match value.checked_add(align.as_usize() - 1) {
+         Some(v) => Some(v & align.mask()),
+         None => None,
+     }
+ }

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Re: linux-next: manual merge of the rust tree with the origin tree

[Miguel Ojeda]

On Fri, Apr 3, 2026 at 2:35 PM Mark Brown <broonie@kernel.org> wrote:
>
>  +use core::mem::{
>  +    align_of,
>  +    size_of, //
>  +};
>   use core::num::NonZero;

Looks good -- it could be nice to take the chance to "merge" these two:

    use core::{
        mem::{
            align_of,
            size_of, //
        },
        num::NonZero, //
    };

Thanks as usual!

Cheers,
Miguel

linux-next: manual merge of the rust tree with the origin tree

[Mark Brown]

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Hi all,

Today's linux-next merge of the rust tree got a conflict in:

  scripts/Makefile.build

between commit:

  f41941aab3acd ("rust: ptr: add projection infrastructure")

from the origin tree and commit:

  560a7a9b9267f ("rust: add `const_assert!` macro")

from the rust tree.

I fixed it up (see below) and can carry the fix as necessary. This
is now fixed as far as linux-next is concerned, but any non trivial
conflicts should be mentioned to your upstream maintainer when your tree
is submitted for merging.  You may also want to consider cooperating
with the maintainer of the conflicting tree to minimise any particularly
complex conflicts.

diff --cc scripts/Makefile.build
index 3652b85be5459,a6d1a2b210aaa..0000000000000
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@@ -310,7 -310,7 +310,8 @@@ $(obj)/%.lst: $(obj)/%.c FORC
  
  # The features in this list are the ones allowed for non-`rust/` code.
  #
 +#   - Stable since Rust 1.79.0: `feature(slice_ptr_len)`.
+ #   - Stable since Rust 1.79.0: `feature(inline_const)`.
  #   - Stable since Rust 1.81.0: `feature(lint_reasons)`.
  #   - Stable since Rust 1.82.0: `feature(asm_const)`,
  #     `feature(offset_of_nested)`, `feature(raw_ref_op)`.
@@@ -321,7 -320,7 +322,7 @@@
  #
  # Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on
  # the unstable features in use.
- rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,offset_of_nested,raw_ref_op,slice_ptr_len,strict_provenance,used_with_arg
 -rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,inline_const,lint_reasons,offset_of_nested,raw_ref_op,used_with_arg
++rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,inline_const,lint_reasons,offset_of_nested,raw_ref_op,slice_ptr_lenstrict_provenance,used_with_arg
  
  # `--out-dir` is required to avoid temporaries being created by `rustc` in the
  # current working directory, which may be not accessible in the out-of-tree

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Re: linux-next: manual merge of the rust tree with the origin tree

[Gary Guo]

On Mon Mar 30, 2026 at 2:17 PM BST, Mark Brown wrote:
> Hi all,
>
> Today's linux-next merge of the rust tree got a conflict in:
>
>   scripts/Makefile.build
>
> between commit:
>
>   f41941aab3acd ("rust: ptr: add projection infrastructure")

This commit is in v7.0-rc4 and later. Miguel, perhaps do a back merge to resolve
the conflict?

>
> from the origin tree and commit:
>
>   560a7a9b9267f ("rust: add `const_assert!` macro")
>
> from the rust tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> diff --cc scripts/Makefile.build
> index 3652b85be5459,a6d1a2b210aaa..0000000000000
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@@ -310,7 -310,7 +310,8 @@@ $(obj)/%.lst: $(obj)/%.c FORC
>   
>   # The features in this list are the ones allowed for non-`rust/` code.
>   #
>  +#   - Stable since Rust 1.79.0: `feature(slice_ptr_len)`.
> + #   - Stable since Rust 1.79.0: `feature(inline_const)`.

I think we would want the lines to be merged on rust-next. This is fine on
linux-next, though.

>   #   - Stable since Rust 1.81.0: `feature(lint_reasons)`.
>   #   - Stable since Rust 1.82.0: `feature(asm_const)`,
>   #     `feature(offset_of_nested)`, `feature(raw_ref_op)`.
> @@@ -321,7 -320,7 +322,7 @@@
>   #
>   # Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on
>   # the unstable features in use.
> - rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,lint_reasons,offset_of_nested,raw_ref_op,slice_ptr_len,strict_provenance,used_with_arg
>  -rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,inline_const,lint_reasons,offset_of_nested,raw_ref_op,used_with_arg
> ++rust_allowed_features := asm_const,asm_goto,arbitrary_self_types,inline_const,lint_reasons,offset_of_nested,raw_ref_op,slice_ptr_lenstrict_provenance,used_with_arg

I think this is missing a comma between slice_ptr_len and strict_provenance.

>   
>   # `--out-dir` is required to avoid temporaries being created by `rustc` in the
>   # current working directory, which may be not accessible in the out-of-tree

Thanks,
Gary

Re: linux-next: manual merge of the rust tree with the origin tree

[Miguel Ojeda]

On Mon, Mar 30, 2026 at 3:26 PM Gary Guo <gary@garyguo.net> wrote:
>
> I think this is missing a comma between slice_ptr_len and strict_provenance.

Indeed, it looks like it -- good eyes!

Also, nit: the line

    #   - Stable since Rust 1.79.0: `feature(slice_ptr_len)`,

should use a period instead of a comma at the end. But, actually, to
be consistent with the others, we should probably do:

    #   - Stable since Rust 1.79.0: `feature(slice_ptr_len)`,
    #     `feature(inline_const)`.

To be fair, perhaps we should use the "one per line" style, but meh,
most of this goes away with the bump and we will have another conflict
soon, so it does not matter much.

Thanks!

Cheers,
Miguel

Re: linux-next: manual merge of the rust tree with the origin tree

[Miguel Ojeda]

On Mon, Mar 30, 2026 at 3:30 PM Miguel Ojeda
<miguel.ojeda.sandonis@gmail.com> wrote:
>
> should use a period instead of a comma at the end.

Please disregard that bit -- somehow I saw a comma (perhaps recalling
the fix I did in `rust-next` for that commit).

Cheers,
Miguel

linux-next: manual merge of the rust tree with the origin tree

[broonie]

Hi all,

Today's linux-next merge of the rust tree got a conflict in:

  tools/include/linux/lockdep.h

between commit:

  3a49cc22d31ec ("tools/lib/lockdep: drop leftover liblockdep headers")

from the origin tree and commit:

  ab4cc3d9c564d ("kallsyms: increase maximum kernel symbol length to 512")

from the rust tree.

I fixed it up by removing lockdep.h again and can carry the fix as
necessary. This is now fixed as far as linux-next is concerned, but any
non trivial conflicts should be mentioned to your upstream maintainer
when your tree is submitted for merging.  You may also want to consider
cooperating with the maintainer of the conflicting tree to minimise any
particularly complex conflicts.