diff --git a/.github/workflows/buildkit.yml b/.github/workflows/buildkit.yml
index 161216d983..3e065c7a00 100644
--- a/.github/workflows/buildkit.yml
+++ b/.github/workflows/buildkit.yml
@@ -49,8 +49,6 @@ jobs:
   test:
     runs-on: ubuntu-20.04
     timeout-minutes: 120
-    env:
-      BUILDKIT_REPO: moby/buildkit
     needs:
       - build
     strategy:
diff --git a/hack/buildkit-ref b/hack/buildkit-ref
index b5991ad04e..99d3cf8401 100755
--- a/hack/buildkit-ref
+++ b/hack/buildkit-ref
@@ -1,8 +1,12 @@
 #!/usr/bin/env bash
-# This script returns the current BuildKit ref being used in moby.
+# This script returns the current BuildKit ref and source repository being used.
+# This script will only work with a BuildKit repository hosted on GitHub.
+# If BUILDKIT_REF is already set in the environment, it will be returned as-is.
+#
+# The output of this script may be valid shell script, but is intended for use with
+# GitHub Actions' $GITHUB_ENV.
 
-: "${BUILDKIT_REPO=moby/buildkit}"
-: "${BUILDKIT_REF=}"
+buildkit_pkg=github.com/moby/buildkit
 
 if [ -n "$BUILDKIT_REF" ]; then
 	echo "$BUILDKIT_REF"
@@ -10,16 +14,18 @@ if [ -n "$BUILDKIT_REF" ]; then
 fi
 
 # get buildkit version from vendor.mod
-BUILDKIT_REF=$(./hack/with-go-mod.sh go list -mod=mod -modfile=vendor.mod -u -m -f '{{if .Replace}}{{.Replace.Version}}{{else}}{{.Version}}{{end}}' "github.com/${BUILDKIT_REPO}")
-BUILDKIT_REPO=$(./hack/with-go-mod.sh go list -mod=mod -modfile=vendor.mod -u -m -f '{{if .Replace}}{{.Replace.Path}}{{else}}{{.Path}}{{end}}' "github.com/${BUILDKIT_REPO}")
-BUILDKIT_REPO=${BUILDKIT_REPO#github.com/}
+buildkit_ref=$(./hack/with-go-mod.sh go list -mod=mod -modfile=vendor.mod -u -m -f '{{if .Replace}}{{.Replace.Version}}{{else}}{{.Version}}{{end}}' "$buildkit_pkg")
+buildkit_repo=$(./hack/with-go-mod.sh go list -mod=mod -modfile=vendor.mod -u -m -f '{{if .Replace}}{{.Replace.Path}}{{else}}{{.Path}}{{end}}' "$buildkit_pkg")
+buildkit_repo=${buildkit_repo#github.com/}
 
-if [[ "${BUILDKIT_REF}" == *-*-* ]]; then
+if [[ "${buildkit_ref}" == *-*-* ]]; then
 	# if pseudo-version, figure out just the uncommon sha (https://github.com/golang/go/issues/34745)
-	BUILDKIT_REF=$(echo "${BUILDKIT_REF}" | awk -F"-" '{print $NF}' | awk 'BEGIN{FIELDWIDTHS="7"} {print $1}')
+	buildkit_ref=$(awk -F"-" '{print $NF}' <<< "$buildkit_ref" | awk 'BEGIN{FIELDWIDTHS="7"} {print $1}')
 	# use github api to return full sha to be able to use it as ref
-	BUILDKIT_REF=$(curl -s "https://api.github.com/repos/${BUILDKIT_REPO}/commits/${BUILDKIT_REF}" | jq -r .sha)
+	buildkit_ref=$(curl -s "https://api.github.com/repos/${buildkit_repo}/commits/${buildkit_ref}" | jq -r .sha)
 fi
 
-echo "BUILDKIT_REPO=$BUILDKIT_REPO"
-echo "BUILDKIT_REF=$BUILDKIT_REF"
+cat << EOF
+BUILDKIT_REPO=$buildkit_repo
+BUILDKIT_REF=$buildkit_ref
+EOF