diff --git a/listings/listing_7.5.cpp b/listings/listing_7.5.cpp
index b4e44c5..e172054 100644
--- a/listings/listing_7.5.cpp
+++ b/listings/listing_7.5.cpp
@@ -31,7 +31,10 @@ class lock_free_stack
         }
         else
         {
-            chain_pending_node(old_head);
+            if(old_head)
+            {
+                chain_pending_node(old_head);
+            }
             --threads_in_pop;
         }
     }