diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 1755056ce368f8fcdbc5ebe9cd8f25237b452fc3..fdb6e4552e5696be1232bf2396bcb978597eda40 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -76,6 +76,14 @@ check-release:
     variables:
       - $RELEASE == "yes"
 
+# Observed: when several shell with same dependencies are started, deadlock may
+#           occur when building these dependencies. We build these dependencies
+#           before running the rest of the pipeline to avoid that.
+prepare-shell-checkers:
+  stage: prepare
+  script:
+    - ./nix/shell-checkers.sh "true"
+
 ################################################################################
 ### BUILD