[PATCH 2/3] rust: allocator: Use krealloc_aligned() in KernelAllocator::alloc

From: Boqun Feng
Date: Sat Jul 29 2023 - 21:30:08 EST


This fixes the potential issue that when KernelAllocator is used, the
allocation may be mis-aligned due to SLAB's alignment guarantee.

Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
---
rust/kernel/allocator.rs | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/rust/kernel/allocator.rs b/rust/kernel/allocator.rs
index fae11d1fdba7..1aec688cf0e0 100644
--- a/rust/kernel/allocator.rs
+++ b/rust/kernel/allocator.rs
@@ -41,9 +41,9 @@ unsafe fn krealloc_aligned(ptr: *mut u8, new_layout: Layout, flags: bindings::gf

unsafe impl GlobalAlloc for KernelAllocator {
unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
- // `krealloc()` is used instead of `kmalloc()` because the latter is
- // an inline function and cannot be bound to as a result.
- unsafe { bindings::krealloc(ptr::null(), layout.size(), bindings::GFP_KERNEL) as *mut u8 }
+ // SAFETY: `ptr::null_mut()` is null and `layout` has a non-zero size by the function safety
+ // requirement.
+ unsafe { krealloc_aligned(ptr::null_mut(), layout, bindings::GFP_KERNEL) }
}

unsafe fn dealloc(&self, ptr: *mut u8, _layout: Layout) {
--
2.41.0