Fix Ysurac/openmptcprouter#3755

mptcp/files/etc/init.d/mptcp

@@ -68,7 +68,7 @@ global_multipath_settings() {
 		[ -z "$mptcp_stale_loss_cnt" ] || sysctl -qew net.mptcp.stale_loss_cnt="$mptcp_stale_loss_cnt"
 		[ -z "$mptcp_pm_type" ] || sysctl -qew net.mptcp.pm_type="$mptcp_pm_type"
 		[ -z "$mptcp_allow_join_initial_addr_port" ] || sysctl -qew net.mptcp.allow_join_initial_addr_port="$mptcp_allow_initial_addr_port"
-		if [ -n "$mptcp_scheduler" ]; then
+		if [ -n "$mptcp_scheduler" ] && [ -d /usr/share/bpf/scheduler ]; then
 			for scheduler in $(ls -1 /usr/share/bpf/scheduler/*.o); do
 				bpftool struct_ops register $scheduler >/dev/null 2>&1
 			done