--- x/include/net/net_namespace.h
+++ y/include/net/net_namespace.h
@@ -328,6 +328,7 @@ static inline void __netns_tracker_alloc
 					 gfp_t gfp)
 {
 #ifdef CONFIG_NET_NS_REFCNT_TRACKER
+	WARN_ON_ONCE(refcount_read(&net->ns.count) < 1);
 	ref_tracker_alloc(refcounted ? &net->refcnt_tracker :
 				       &net->notrefcnt_tracker,
 			  tracker, gfp);