diff --git a/kernel/fstdata.h b/kernel/fstdata.h
index 6263db056..56f0ee51a 100644
--- a/kernel/fstdata.h
+++ b/kernel/fstdata.h
@@ -63,6 +63,7 @@ private:
 	void extractVarNames();
 	void registerVar(const FstVar &var);
 
+	bool fork_vars_had_nested_fork = false;  // Track if nested fork was detected
 	struct fstReaderContext *ctx;
 	std::vector<FstVar> vars;
 	std::map<fstHandle, FstVar> handle_to_var;