diff --git a/pkg/runner/run_context.go b/pkg/runner/run_context.go
index d273fd2..1f0924f 100644
--- a/pkg/runner/run_context.go
+++ b/pkg/runner/run_context.go
@@ -194,6 +194,8 @@ var lxcHelpers string
 
 var startTemplate = template.Must(template.New("start").Parse(`#!/bin/bash -e
 
+exec 5<>/tmp/forgejo-runner-lxc.lock ; flock --timeout 21600 5
+
 LXC_CONTAINER_CONFIG="{{.Config}}"
 LXC_CONTAINER_RELEASE="{{.Release}}"