diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 591a18701..2646c4497 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -11,6 +11,10 @@ on:
       - release-*
   pull_request:
 
+env:
+  # Don't ignore C warnings. Note that the output of "go env CGO_CFLAGS" by default is "-g -O2", so we keep them.
+  CGO_CFLAGS: -g -O2 -Werror
+
 jobs:
   test:
     runs-on: ubuntu-20.04
diff --git a/.github/workflows/validate.yml b/.github/workflows/validate.yml
index 8ad6be73e..78bfe0718 100644
--- a/.github/workflows/validate.yml
+++ b/.github/workflows/validate.yml
@@ -25,6 +25,9 @@ jobs:
 
   compile-buildtags:
     runs-on: ubuntu-20.04
+    env:
+      # Don't ignore C warnings. Note that the output of "go env CGO_CFLAGS" by default is "-g -O2", so we keep them.
+      CGO_CFLAGS: -g -O2 -Werror
     steps:
       - uses: actions/checkout@v2
       - name: compile with no build tags