Zero memory on allocation

kernel/src/allocator.rs

@@ -150,7 +150,8 @@ impl Heap {
             #[cfg(debug_assertions)]
             trace!("Allocating   {:?}", ptr);
         }
-        // FIXME: zero out memory to prevent leaking data
+
+        unsafe { core::ptr::write_bytes(ptr, 0, size) };
 
         assert!(ptr.is_aligned_to(alignment));
         NonNull::new(ptr)
@@ -168,6 +169,7 @@ impl Heap {
         self.bitmap_set_range(start, size, false);
         self.allocated_chunks -= size;
         // FIXME: zero out memory to prevent leaking data
+        //     REPLY: When we zero on alloc, do we really need it?
     }
 
     /// Finds first hole that can fit an allocation of `size` chunks, returns the start of the