kernel/rust, branch linux-6.18.y

rust: str: make NullTerminatedFormatter public

2026-03-19T15:08:24Z

commit 3ac88a9948792b092a4b11323e2abd1ecbe0cc68 upstream. If `CONFIG_BLOCK` is disabled, the following warnings are displayed during build: warning: struct `NullTerminatedFormatter` is never constructed --> ../rust/kernel/str.rs:667:19 | 667 | pub(crate) struct NullTerminatedFormatter<'a> { | ^^^^^^^^^^^^^^^^^^^^^^^ | = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default warning: associated function `new` is never used --> ../rust/kernel/str.rs:673:19 | 671 | impl<'a> NullTerminatedFormatter<'a> { | ------------------------------------ associated function in this implementation 672 | /// Create a new [`Self`] instance. 673 | pub(crate) fn new(buffer: &'a mut [u8]) -> Option> { Fix them by making `NullTerminatedFormatter` public, as it could be useful for drivers anyway. Fixes: cdde7a1951ff ("rust: str: introduce `NullTerminatedFormatter`") Signed-off-by: Alexandre Courbot Reviewed-by: Alice Ryhl Reviewed-by: Andreas Hindborg Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260224-nullterminatedformatter-v1-1-5bef7b9b3d4c@nvidia.com Signed-off-by: Miguel Ojeda Signed-off-by: Greg Kroah-Hartman

rust: kunit: fix warning when !CONFIG_PRINTK

2026-03-12T11:09:52Z

[ Upstream commit 7dd34dfc8dfa92a7244242098110388367996ac3 ] If `CONFIG_PRINTK` is not set, then the following warnings are issued during build: warning: unused variable: `args` --> ../rust/kernel/kunit.rs:16:12 | 16 | pub fn err(args: fmt::Arguments<'_>) { | ^^^^ help: if this is intentional, prefix it with an underscore: `_args` | = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default warning: unused variable: `args` --> ../rust/kernel/kunit.rs:32:13 | 32 | pub fn info(args: fmt::Arguments<'_>) { | ^^^^ help: if this is intentional, prefix it with an underscore: `_args` Fix this by adding a no-op assignment using `args` when `CONFIG_PRINTK` is not set. Fixes: a66d733da801 ("rust: support running Rust documentation tests as KUnit ones") Signed-off-by: Alexandre Courbot Reviewed-by: Alice Ryhl Reviewed-by: David Gow Signed-off-by: Shuah Khan Signed-off-by: Sasha Levin

rust: list: Add unsafe blocks for container_of and safety comments

2026-03-04T12:21:35Z

[ Upstream commit 97b281d7edb2ae662365be2809cd728470119720 ] impl_list_item_mod.rs calls container_of! without unsafe blocks at a couple of places. Since container_of! is unsafe, the blocks are strictly necessary. The problem was so far not visible because the "unsafe-op-in-unsafe-fn" check is a lint rather than a hard compiler error, and Rust suppresses lints triggered inside of a macro from another crate. Thus, the error becomes only visible once someone from within the kernel crate tries to use linked lists: error[E0133]: call to unsafe function `core::ptr::mut_ptr::::byte_sub` is unsafe and requires unsafe block --> rust/kernel/lib.rs:252:29 | 252 | let container_ptr = field_ptr.byte_sub(offset).cast::<$Container>(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^ call to unsafe function | ::: rust/kernel/drm/jq.rs:98:1 | 98 | / impl_list_item! { 99 | | impl ListItem<0> for BasicItem { using ListLinks { self.links }; } 100 | | } | |_- in this macro invocation | note: an unsafe function restricts its caller, but its body is safe by default --> rust/kernel/list/impl_list_item_mod.rs:216:13 | 216 | unsafe fn view_value(me: *mut $crate::list::ListLinks<$num>) -> *const Self { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | ::: rust/kernel/drm/jq.rs:98:1 | 98 | / impl_list_item! { 99 | | impl ListItem<0> for BasicItem { using ListLinks { self.links }; } 100 | | } | |_- in this macro invocation = note: requested on the command line with `-D unsafe-op-in-unsafe-fn` = note: this error originates in the macro `$crate::container_of` which comes from the expansion of the macro `impl_list_item` Therefore, add unsafe blocks to container_of! calls to fix the issue. [ As discussed, let's fix the build for those that want to use the macro within the `kernel` crate now and we can discuss the proper safety comments afterwards. Thus I removed the ones from the patch. However, we cannot just avoid the comments with `CLIPPY=1`, so I provided placeholders for now, like we did in the past. They were also needed for an `unsafe impl`. While I am not happy about it, it isn't worse than the current status (the comments were meant to be there), and at least this shows what is missing -- our pre-existing "good first issue" [1] may motivate new contributors to complete them properly. Finally, I moved one of the existing safety comments one line down so that Clippy could locate it. Link: https://github.com/Rust-for-Linux/linux/issues/351 [1] - Miguel ] Cc: stable@vger.kernel.org Fixes: c77f85b347dd ("rust: list: remove OFFSET constants") Suggested-by: Alice Ryhl Signed-off-by: Philipp Stanner Reviewed-by: Gary Guo Reviewed-by: Alice Ryhl Link: https://patch.msgid.link/20260216131613.45344-3-phasta@kernel.org [ Fixed formatting. Reworded to fix the lint suppression explanation. Indent build error. - Miguel ] Signed-off-by: Miguel Ojeda Signed-off-by: Sasha Levin

rust: pin-init: replace clippy `expect` with `allow`

2026-03-04T12:21:33Z

[ Upstream commit a58b8764aed9648357b1c5b6368c9943ba33b7f9 ] `clippy` has changed behavior in [1] (Rust 1.95) where it no longer warns about the `let_and_return` lint when a comment is placed between the let binding and the return expression. Nightly thus fails to build, because the expectation is no longer fulfilled. Thus replace the expectation with an `allow`. [ The errors were: error: this lint expectation is unfulfilled --> rust/pin-init/src/lib.rs:1279:10 | 1279 | #[expect(clippy::let_and_return)] | ^^^^^^^^^^^^^^^^^^^^^^ | = note: `-D unfulfilled-lint-expectations` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(unfulfilled_lint_expectations)]` error: this lint expectation is unfulfilled --> rust/pin-init/src/lib.rs:1295:10 | 1295 | #[expect(clippy::let_and_return)] | ^^^^^^^^^^^^^^^^^^^^^^ - Miguel ] Link: https://github.com/rust-lang/rust-clippy/pull/16461 [1] Signed-off-by: Benno Lossin Cc: stable@vger.kernel.org # Needed in 6.18.y and later. Link: https://patch.msgid.link/20260215132232.1549861-1-lossin@kernel.org Signed-off-by: Miguel Ojeda Signed-off-by: Sasha Levin

rust: irq: add `'static` bounds to irq callbacks

2026-03-04T12:21:33Z

[ Upstream commit 621609f1e5ca43a75edd497dd1c28bd84aa66433 ] These callback functions take a generic `T` that is used in the body as the generic argument in `Registration` and `ThreadedRegistration`. Those types require `T: 'static`, but due to a compiler bug this requirement isn't propagated to the function. Thus add the bound. This was caught in the upstream Rust CI [1]. [ The three errors looked similar and will start appearing with Rust 1.95.0 (expected 2026-04-16). The first one was: error[E0310]: the parameter type `T` may not live long enough Error: --> rust/kernel/irq/request.rs:266:43 | 266 | let registration = unsafe { &*(ptr as *const Registration) }; | ^^^^^^^^^^^^^^^^^^^^^^ | | | the parameter type `T` must be valid for the static lifetime... | ...so that the type `T` will meet its required lifetime bounds | help: consider adding an explicit lifetime bound | 264 | unsafe extern "C" fn handle_irq_callback(_irq: i32, ptr: *mut c_void) -> c_uint { | +++++++++ - Miguel ] Link: https://github.com/rust-lang/rust/pull/149389 [1] Signed-off-by: Benno Lossin Cc: stable@vger.kernel.org Fixes: 29e16fcd67ee ("rust: irq: add &Device argument to irq callbacks") Reviewed-by: Gary Guo Reviewed-by: Daniel Almeida Acked-by: Danilo Krummrich Link: https://lore.kernel.org/rust-for-linux/20260217222425.8755-1-cole@unwrap.rs/ Link: https://patch.msgid.link/20260214092740.3201946-1-lossin@kernel.org Signed-off-by: Miguel Ojeda Signed-off-by: Sasha Levin

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

2026-03-04T12:21:26Z

[ 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/drm: Fix Registration::{new,new_foreign_owned}() docs

2026-03-04T12:21:15Z

[ Upstream commit 638eeda8abaa3e6afe6bd5758ef8045a7f33b9a0 ] Looks like we've actually had a malformed rustdoc reference in the rustdocs for Registration::new_foreign_owned() for a while that, when fixed, still couldn't resolve properly because it refers to a private item. This is probably leftover from when Registration::new() was public, so drop the documentation from that function and fixup the documentation for Registration::new_foreign_owned(). Signed-off-by: Lyude Paul Acked-by: Danilo Krummrich Fixes: 0600032c54b7 ("rust: drm: add DRM driver registration") Cc: # v6.16+ Link: https://patch.msgid.link/20260122221037.3462081-1-lyude@redhat.com Signed-off-by: Sasha Levin

rust: cpufreq: always inline functions using build_assert with arguments

2026-03-04T12:19:37Z

[ Upstream commit 8c8b12a55614ea05953e8d695e700e6e1322a05d ] `build_assert` relies on the compiler to optimize out its error path. Functions using it with its arguments must thus always be inlined, otherwise the error path of `build_assert` might not be optimized out, triggering a build error. Signed-off-by: Alexandre Courbot Reviewed-by: Daniel Almeida Signed-off-by: Viresh Kumar Signed-off-by: Sasha Levin

rust: task: restrict Task::group_leader() to current

2026-02-26T22:59:18Z

[ Upstream commit 105ddfb2d2b3acec7a7d9695463df48733d91e6c ] The Task::group_leader() method currently allows you to access the group_leader() of any task, for example one you hold a refcount to. But this is not safe in general since the group leader could change when a task exits. See for example commit a15f37a40145c ("kernel/sys.c: fix the racy usage of task_lock(tsk->group_leader) in sys_prlimit64() paths"). All existing users of Task::group_leader() call this method on current, which is guaranteed running, so there's not an actual issue in Rust code today. But to prevent code in the future from making this mistake, restrict Task::group_leader() so that it can only be called on current. There are some other cases where accessing task->group_leader is okay. For example it can be safe if you hold tasklist_lock or rcu_read_lock(). However, only supporting current->group_leader is sufficient for all in-tree Rust users of group_leader right now. Safe Rust functionality for accessing it under rcu or while holding tasklist_lock may be added in the future if required by any future Rust module. This patch is a bugfix in that it prevents users of this API from writing incorrect code. It doesn't change behavior of correct code. Link: https://lkml.kernel.org/r/20260107-task-group-leader-v2-1-8fbf816f2a2f@google.com Signed-off-by: Alice Ryhl Fixes: 313c4281bc9d ("rust: add basic `Task`") Reported-by: Oleg Nesterov Closes: https://lore.kernel.org/all/aTLnV-5jlgfk1aRK@redhat.com/ Reviewed-by: Boqun Feng Reviewed-by: Gary Guo Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Björn Roy Baron Cc: Christian Brauner Cc: Danilo Krummrich Cc: FUJITA Tomonori Cc: Miguel Ojeda Cc: Panagiotis Foliadis Cc: Shankari Anand Cc: Trevor Gross Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin

rust: driver: fix broken intra-doc links to example driver types

2026-02-19T15:31:31Z

commit 4c9f6a782f6078dc94450fcb22e65d520bfa0775 upstream. The `auxiliary` and `pci` modules are conditional on `CONFIG_AUXILIARY_BUS` and `CONFIG_PCI` respectively. When these are disabled, the intra-doc links to `auxiliary::Driver` and `pci::Driver` break, causing rustdoc warnings (or errors with `-D warnings`). error: unresolved link to `kernel::auxiliary::Driver` --> rust/kernel/driver.rs:82:28 | 82 | //! [`auxiliary::Driver`]: kernel::auxiliary::Driver | ^^^^^^^^^^^^^^^^^^^^^^^^^ no item named `auxiliary` in module `kernel` Fix this by making the documentation for these examples conditional on the corresponding configuration options. Fixes: 970a7c68788e ("driver: rust: expand documentation for driver infrastructure") Signed-off-by: Alice Ryhl Reported-by: FUJITA Tomonori Closes: https://lore.kernel.org/rust-for-linux/20251209.151817.744108529426448097.fujita.tomonori@gmail.com/ Link: https://patch.msgid.link/20251227-driver-types-v1-1-1916154fbe5e@google.com Signed-off-by: Danilo Krummrich Signed-off-by: Greg Kroah-Hartman