Commit b7ed2b6f authored by Asahi Lina's avatar Asahi Lina Committed by Miguel Ojeda
Browse files

rust: alloc: Fix `ArrayLayout` allocations 



We were accidentally allocating a layout for the *square* of the object
size due to a variable shadowing mishap.

Fixes memory bloat and page allocation failures in drm/asahi.

Reported-by: default avatarJanne Grunau <j@jannau.net>
Fixes: 9e7bbfa1 ("rust: alloc: introduce `ArrayLayout`")
Signed-off-by: default avatarAsahi Lina <lina@asahilina.net>
Acked-by: default avatarDanilo Krummrich <dakr@kernel.org>
Reviewed-by: default avatarNeal Gompa <neal@gompa.dev>
Link: https://lore.kernel.org/r/20241123-rust-fix-arraylayout-v1-1-197e64c95bd4@asahilina.net


Signed-off-by: default avatarMiguel Ojeda <ojeda@kernel.org>
parent b160dc46

rust/kernel/alloc/layout.rs

+1 −1
Original line number Diff line number Diff line
@@ -45,7 +45,7 @@ pub const fn empty() -> Self { 
    /// When `len * size_of::<T>()` overflows or when `len * size_of::<T>() > isize::MAX`.

    pub const fn new(len: usize) -> Result<Self, LayoutError> {

        match len.checked_mul(core::mem::size_of::<T>()) {

            Some(len) if len <= ISIZE_MAX => {

            Some(size) if size <= ISIZE_MAX => {

                // INVARIANT: We checked above that `len * size_of::<T>() <= isize::MAX`.

                Ok(Self {

                    len,