3 files changed, 15 insertions, 17 deletions
diff --git a/rust/kernel/alloc/allocator.rs b/rust/kernel/alloc/allocator.rs
index 229642960cd1..e6ea601f38c6 100644
--- a/rust/kernel/alloc/allocator.rs
+++ b/rust/kernel/alloc/allocator.rs
@@ -18,23 +18,16 @@ pub(crate) unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: F
     // Customized layouts from `Layout::from_size_align()` can have size < align, so pad first.
     let layout = new_layout.pad_to_align();
 
-    let mut size = layout.size();
-
-    if layout.align() > bindings::ARCH_SLAB_MINALIGN {
-        // The alignment requirement exceeds the slab guarantee, thus try to enlarge the size
-        // to use the "power-of-two" size/alignment guarantee (see comments in `kmalloc()` for
-        // more information).
-        //
-        // Note that `layout.size()` (after padding) is guaranteed to be a multiple of
-        // `layout.align()`, so `next_power_of_two` gives enough alignment guarantee.
-        size = size.next_power_of_two();
-    }
+    // Note that `layout.size()` (after padding) is guaranteed to be a multiple of `layout.align()`
+    // which together with the slab guarantees means the `krealloc` will return a properly aligned
+    // object (see comments in `kmalloc()` for more information).
+    let size = layout.size();
 
     // SAFETY:
     // - `ptr` is either null or a pointer returned from a previous `k{re}alloc()` by the
     //   function safety requirement.
-    // - `size` is greater than 0 since it's either a `layout.size()` (which cannot be zero
-    //   according to the function safety requirement) or a result from `next_power_of_two()`.
+    // - `size` is greater than 0 since it's from `layout.size()` (which cannot be zero according
+    //   to the function safety requirement)
     unsafe { bindings::krealloc(ptr as *const core::ffi::c_void, size, flags.0) as *mut u8 }
 }
 
diff --git a/rust/kernel/alloc/box_ext.rs b/rust/kernel/alloc/box_ext.rs
index 829cb1c1cf9e..9f1c1c489189 100644
--- a/rust/kernel/alloc/box_ext.rs
+++ b/rust/kernel/alloc/box_ext.rs
@@ -21,8 +21,10 @@ pub trait BoxExt<T>: Sized {
 
 impl<T> BoxExt<T> for Box<T> {
     fn new(x: T, flags: Flags) -> Result<Self, AllocError> {
-        let b = <Self as BoxExt<_>>::new_uninit(flags)?;
-        Ok(Box::write(b, x))
+        let mut b = <Self as BoxExt<_>>::new_uninit(flags)?;
+        b.write(x);
+        // SAFETY: We just wrote to it.
+        Ok(unsafe { b.assume_init() })
     }
 
     #[cfg(any(test, testlib))]
diff --git a/rust/kernel/alloc/vec_ext.rs b/rust/kernel/alloc/vec_ext.rs
index e9a81052728a..1297a4be32e8 100644
--- a/rust/kernel/alloc/vec_ext.rs
+++ b/rust/kernel/alloc/vec_ext.rs
@@ -4,7 +4,6 @@
 
 use super::{AllocError, Flags};
 use alloc::vec::Vec;
-use core::ptr;
 
 /// Extensions to [`Vec`].
 pub trait VecExt<T>: Sized {
@@ -141,7 +140,11 @@ impl<T> VecExt<T> for Vec<T> {
         // `krealloc_aligned`. A `Vec<T>`'s `ptr` value is not guaranteed to be NULL and might be
         // dangling after being created with `Vec::new`. Instead, we can rely on `Vec<T>`'s capacity
         // to be zero if no memory has been allocated yet.
-        let ptr = if cap == 0 { ptr::null_mut() } else { old_ptr };
+        let ptr = if cap == 0 {
+            core::ptr::null_mut()
+        } else {
+            old_ptr
+        };
 
         // SAFETY: `ptr` is valid because it's either NULL or comes from a previous call to
         // `krealloc_aligned`. We also verified that the type is not a ZST.