diff --git a/lightningd/peer_control.c b/lightningd/peer_control.c
index 8e3676370..b889d0e2b 100644
--- a/lightningd/peer_control.c
+++ b/lightningd/peer_control.c
@@ -257,6 +257,7 @@ void peer_fail_transient(struct peer *peer, const char *fmt, ...)
 
 #if DEVELOPER
 	if (dev_disconnect_permanent(peer->ld)) {
+		tal_free(why);
 		peer_internal_error(peer, "dev_disconnect permfail");
 		return;
 	}