diff --git a/gtests/net/packetdrill/config.c b/gtests/net/packetdrill/config.c
index c77f37d6984d638a61c013943fec1230dab630be..afe3d3f36f3721a154e88548334da534d1bf8c43 100644
--- a/gtests/net/packetdrill/config.c
+++ b/gtests/net/packetdrill/config.c
@@ -597,7 +597,6 @@ static void process_option(int opt, char *optarg, struct config *config,
 		config->tun_device = strdup(optarg);
 		break;
 	case OPT_PERSISTENT_TUN_DEV:
-		assert(optarg != NULL);
 		config->persistent_tun_device = true;
 		break;
 #endif