From a5c7d35e2fd3e24c411816c91f8f6cc78e652e0c Mon Sep 17 00:00:00 2001 From: Nikolai Grlica Date: Mon, 10 Aug 2026 15:03:35 +0000 Subject: rust: kernel: list: fix incorrect pop_back example comment The example uses pop_back(), but the accompanying comment says pop_front(). Update the comment to match the example. Signed-off-by: Nikolai Grlica Cc: stable@vger.kernel.org Fixes: bf87a41b85d6 ("rust: list: Add an example for `ListLinksSelfPtr` usage") Link: https://patch.msgid.link/20260810150322.61809-1-nikolai@nikolaigrlica.dev Signed-off-by: Miguel Ojeda --- rust/kernel/list.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'rust/kernel') diff --git a/rust/kernel/list.rs b/rust/kernel/list.rs index 406e3a028c55..0f367264ee2e 100644 --- a/rust/kernel/list.rs +++ b/rust/kernel/list.rs @@ -249,7 +249,7 @@ pub use self::arc_field::{ /// assert_eq!(list.iter().count(), 3); /// } /// -/// // Pop the items from the list using `pop_front()` and verify the content. +/// // Pop the items from the list using `pop_back()` and verify the content. /// { /// assert_eq!(list.pop_back().ok_or(EINVAL)?.value.foo(), ("a", 15)); /// assert_eq!(list.pop_back().ok_or(EINVAL)?.value.foo(), ("a", 32)); -- cgit v1.2.3 From dea1bf38143f8505747c19b953ef12fb809d5d77 Mon Sep 17 00:00:00 2001 From: FUJITA Tomonori Date: Sun, 9 Aug 2026 22:48:58 +0900 Subject: rust: jump_label: skip arch-specific asm in `testlib` builds Running `make rusttest` with `ARCH=` set to an architecture other than the host's may fail in the future, e.g. `ARCH=arm64` on an x86_64 host: error: alignment must be a power of 2 --> rust/kernel/jump_label.rs:51:13 | 51 | include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_static_branch_asm.rs")); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | note: instantiated into assembly here --> :3:10 | 3 | .align 3 | ^ The reason is that `rusttest` builds the kernel crate as a host library: it passes the `CONFIG_*` cfgs of the configured architecture, but not `--target`, so code generation happens for the host. `arch_static_branch!` then selects the arch-specific inline asm arm based on CONFIG_*, and the host assembler rejects it. This does not happen with the current master because `arch_static_branch!` has no user inside the kernel crate itself yet, but fix it now to avoid surprises later. Signed-off-by: FUJITA Tomonori Link: https://patch.msgid.link/20260809134858.1219036-1-tomo@flapping.org [ Reworded slightly to clarify it "may fail in the future". - Miguel ] Signed-off-by: Miguel Ojeda --- rust/kernel/jump_label.rs | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'rust/kernel') diff --git a/rust/kernel/jump_label.rs b/rust/kernel/jump_label.rs index 4e974c768dbd..f54cedcb6fd5 100644 --- a/rust/kernel/jump_label.rs +++ b/rust/kernel/jump_label.rs @@ -44,6 +44,7 @@ const _: &str = include!(concat!( #[macro_export] #[doc(hidden)] +#[cfg(not(testlib))] #[cfg(CONFIG_JUMP_LABEL)] macro_rules! arch_static_branch { ($key:path, $keytyp:ty, $field:ident, $branch:expr) => {'my_label: { @@ -61,6 +62,17 @@ macro_rules! arch_static_branch { }}; } +#[macro_export] +#[doc(hidden)] +#[cfg(testlib)] +#[cfg(CONFIG_JUMP_LABEL)] +macro_rules! arch_static_branch { + ($key:path, $keytyp:ty, $field:ident, $branch:expr) => { + // The asm falls through until patched, which never happens on the host. + false + }; +} + #[cfg(CONFIG_JUMP_LABEL)] pub use arch_static_branch; -- cgit v1.2.3 From 7dd6343fc127935425a81a8f1989907996c2868d Mon Sep 17 00:00:00 2001 From: Younes Akhouayri Date: Sat, 22 Aug 2026 10:44:47 +0200 Subject: rust: num: restrict bool conversion to unsigned Bounded From turns true into 1. A signed Bounded with N = 1 can hold only -1 and 0. The current implementation can therefore create a value that breaks Bounded's invariant. Deref relies on that invariant and calls unreachable_unchecked() when it is broken, so safe Rust can reach undefined behavior. The other primitive conversions require the source and destination to have the same signedness. Treat bool as an unsigned one-bit value and allow conversions between bool and Bounded only when the backing integer type is unsigned. Fixes: 01e345e82ec3 ("rust: num: add Bounded integer wrapping type") Closes: https://lore.kernel.org/rust-for-linux/OzuVxu0--J-9@younes.io/ Cc: stable@vger.kernel.org Suggested-by: Alexandre Courbot Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Younes Akhouayri Reviewed-by: Alexandre Courbot Link: https://patch.msgid.link/20260822-fix-rust-bounded-from-bool-submit-v4-1-aa780bfe7f30@younes.io Signed-off-by: Miguel Ojeda --- rust/kernel/num/bounded.rs | 30 +++++++++++++++++++++--------- 1 file changed, 21 insertions(+), 9 deletions(-) (limited to 'rust/kernel') diff --git a/rust/kernel/num/bounded.rs b/rust/kernel/num/bounded.rs index d192610a687d..2a2b0a4bca5e 100644 --- a/rust/kernel/num/bounded.rs +++ b/rust/kernel/num/bounded.rs @@ -13,7 +13,10 @@ use core::{ }; use kernel::{ - num::Integer, + num::{ + Integer, + Unsigned, // + }, prelude::*, // }; @@ -174,13 +177,16 @@ fn fits_within(value: T, num_bits: u32) -> bool { /// // `u8` (regardless of the passed value). /// // let _ = Bounded::::from(10u8); /// -/// // Booleans can be converted into single-bit `Bounded`s. +/// // Booleans can be converted into unsigned `Bounded`s. /// /// let v = Bounded::::from(false); /// assert_eq!(v.get(), 0); /// /// let v = Bounded::::from(true); /// assert_eq!(v.get(), 1); +/// +/// // This does not build because `i8` is signed. +/// // let _ = Bounded::::from(true); /// ``` /// /// Infallible conversions from a [`Bounded`] to a primitive integer are also supported, and @@ -203,12 +209,16 @@ fn fits_within(value: T, num_bits: u32) -> bool { /// let _v = Bounded::::new::<10>(); /// // assert_eq!(u8::from(_v), 10); /// -/// // Single-bit `Bounded`s can be converted into a boolean. +/// // Unsigned single-bit `Bounded`s can be converted into a boolean. /// let v = Bounded::::new::<1>(); /// assert_eq!(bool::from(v), true); /// /// let v = Bounded::::new::<0>(); /// assert_eq!(bool::from(v), false); +/// +/// // This does not build because `i8` is signed. +/// // let v = Bounded::::new::<-1>(); +/// // let _ = bool::from(v); /// ``` /// /// Fallible conversions from any primitive integer to any [`Bounded`] are also supported using the @@ -1109,31 +1119,33 @@ impl_into_primitive!( i8 i16 i32 i64 isize ); -// Single-bit `Bounded`s can be converted from/to a boolean. +// Unsigned single-bit `Bounded`s can be converted to a boolean. impl From> for bool where - T: Integer + Zeroable, + T: Integer + Zeroable, { fn from(value: Bounded) -> Self { value.get() != Zeroable::zeroed() } } +// Booleans can be converted to unsigned `Bounded`s. + impl From for Bounded where - T: Integer + From, + T: Integer + From, { fn from(value: bool) -> Self { - // SAFETY: A boolean can be represented using a single bit, and thus fits within any - // integer type for any `N` > 0. + // SAFETY: A boolean is represented by `0` or `1`, so it fits within any valid unsigned + // `Bounded` width. unsafe { Self::__new(T::from(value)) } } } impl Bounded where - T: Integer + Zeroable, + T: Integer + Zeroable, { /// Converts this [`Bounded`] into a [`bool`]. /// -- cgit v1.2.3