diff --git a/README.md b/README.md
index 7a1bbb4..7b1145b 100644
--- a/README.md
+++ b/README.md
@@ -198,3 +198,10 @@ Check if timer's bug occured:
 ```
 ls | grep -P '^naive-|^rrh-|^rr-|^orig-' | while read n; do echo "$n "; grep 'bug' $n/log/client-measlat-stderr.log; done
 ```
+
+Check if a free() invalid pointer bug occured:
+
+```
+grep 'free' naive-*/log/*-donar-*.log
+grep -rn 'free()' .
+```