diff --git a/sandbox/vm/cache.c b/sandbox/vm/cache.c
index fa87849..1925dbc 100644
--- a/sandbox/vm/cache.c
+++ b/sandbox/vm/cache.c
@@ -16,9 +16,9 @@ vm_cache_t *vm_cache_create(const char *name, size_t objsz, vm_cache_flags_t fla
 	new_cache->c_name = name;
 	new_cache->c_obj_size = objsz;
 	new_cache->c_flags = flags;
-	
+
 	vm_cache_init(new_cache);
-	
+
 	return new_cache;
 }
 
@@ -31,7 +31,7 @@ void vm_cache_init(vm_cache_t *cache)
 
 	size_t available = vm_page_order_to_bytes(cache->c_page_order);
 	size_t space_per_item = cache->c_obj_size;
-	
+
 	/* align to 16-byte boundary */
 	if (space_per_item & 0xF) {
 		space_per_item &= ~0xF;
@@ -43,7 +43,7 @@ void vm_cache_init(vm_cache_t *cache)
 	if (!(cache->c_flags & VM_CACHE_OFFSLAB)) {
 		available -= sizeof(vm_slab_t);
 	}
-		
+
 	/* one entry in the freelist per object slot */
 	space_per_item += sizeof(unsigned int);
 
@@ -51,6 +51,8 @@ void vm_cache_init(vm_cache_t *cache)
 	cache->c_slabs_full = QUEUE_INIT;
 	cache->c_slabs_partial = QUEUE_INIT;
 	cache->c_slabs_empty = QUEUE_INIT;
+
+	cache->c_hdr_size = sizeof(vm_slab_t) + (sizeof(unsigned int) * cache->c_obj_count);
 }
 
 void vm_cache_destroy(vm_cache_t *cache)