`Heap::dealloc` is unsound

[nikitax44]

it is possible to cause segfault in entirely safe code:

fn main() {
    let mut heap = buddy_system_allocator::Heap<10>::new();
    heap.dealloc(
        std::ptr::NonNull::dangling(),
        std::alloc::Layout::from_size_align(1, 1).unwrap(),
    );
}

[jiegec]

Yes, but as this is an allocator, we don't want to support such case, since the expected usage is via global_allocator.

[nikitax44]

this function should be unsafe. you shouldn't expose safe functions that may cause UB. the unsafe attribute does not conflict with global allocator use case as GlobalAlloc::dealloc is declared to be unsafe.

[jiegec]

this function should be unsafe. you shouldn't expose safe functions that may cause UB. the unsafe attribute does not conflict with global allocator use case as GlobalAlloc::dealloc is declared to be unsafe.

Okay, please add the unsafe attribute in a pull request.