diff --git a/libs/neonart/src/allocator/slab.rs b/libs/neonart/src/allocator/slab.rs
index 29a3cf901a..aabbf6696d 100644
--- a/libs/neonart/src/allocator/slab.rs
+++ b/libs/neonart/src/allocator/slab.rs
@@ -78,12 +78,21 @@ unsafe fn unlink_slab_block(mut list: Option<&mut BlockList>, elem: *mut SlabBlo
     }
 }
 
-#[derive(Default, Debug)]
+#[derive(Debug)]
 struct BlockList {
     head: *mut SlabBlockHeader,
     tail: *mut SlabBlockHeader,
 }
 
+impl Default for BlockList {
+    fn default() -> Self {
+        BlockList {
+            head: std::ptr::null_mut(),
+            tail: std::ptr::null_mut(),
+        }
+    }
+}
+
 impl BlockList {
     unsafe fn push_head(&mut self, elem: *mut SlabBlockHeader) {
         unsafe {