diff --git a/.github/workflows/sanity_check.yml b/.github/workflows/sanity_check.yml
index 1f5f93bfb..01dd21866 100644
--- a/.github/workflows/sanity_check.yml
+++ b/.github/workflows/sanity_check.yml
@@ -30,6 +30,9 @@ jobs:
       with:
         args: https://raw.githubusercontent.com/llvm-mirror/clang/master/tools/clang-format/clang-format-diff.py
 
+    - name: Found merge base
+      run: git merge-base upstream/master HEAD
+
     - name: Check format 1
       run: |
         build_tools/format-diff.sh -c