diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 7b273b36e..756998719 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -31,18 +31,17 @@ jobs:
     - name: Test build
       run: go test ./...
 
-    # TODO: set up slack notification.
-    # - uses: k0kubun/action-slack@v2.0.0
-    #   with:
-    #     payload: |
-    #       {
-    #         "attachments": [{
-    #           "text": "${{ job.status }}: ${{ github.workflow }} <https://github.com/${{ github.repository }}/commit/${{ github.sha }}/checks|${{ env.COMMIT_DATE }} #${{ env.COMMIT_NUMBER_OF_DAY }}> " +
-    #                   "(<https://github.com/${{ github.repository }}/commit/${{ github.sha }}|" + "${{ github.sha }}".substring(0, 10) + ">) " +
-    #                   "of ${{ github.repository }}@" + "${{ github.ref }}".split('/').reverse()[0] + " by ${{ github.event.head_commit.committer.name }}",
-    #           "color": "danger"
-    #         }]
-    #       }
-    #   env:
-    #     SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
-    #   if: failure() && github.event_name == 'push'
+    - uses: k0kubun/action-slack@v2.0.0
+      with:
+        payload: |
+          {
+            "attachments": [{
+              "text": "${{ job.status }}: ${{ github.workflow }} <https://github.com/${{ github.repository }}/commit/${{ github.sha }}/checks|${{ env.COMMIT_DATE }} #${{ env.COMMIT_NUMBER_OF_DAY }}> " +
+                      "(<https://github.com/${{ github.repository }}/commit/${{ github.sha }}|" + "${{ github.sha }}".substring(0, 10) + ">) " +
+                      "of ${{ github.repository }}@" + "${{ github.ref }}".split('/').reverse()[0] + " by ${{ github.event.head_commit.committer.name }}",
+              "color": "danger"
+            }]
+          }
+      env:
+        SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
+      if: failure() && github.event_name == 'push'