diff --git a/lib/librumpuser/rumpfiber.c b/lib/librumpuser/rumpfiber.c
index 94730f4a9344..ac4105a91faa 100644
--- a/lib/librumpuser/rumpfiber.c
+++ b/lib/librumpuser/rumpfiber.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: rumpfiber.c,v 1.5 2014/11/05 01:39:40 pooka Exp $	*/
+/*	$NetBSD: rumpfiber.c,v 1.6 2014/11/08 21:27:04 justin Exp $	*/
 
 /*
  * Copyright (c) 2007-2013 Antti Kantee.  All Rights Reserved.
@@ -68,7 +68,7 @@
 #include "rumpuser_port.h"
 
 #if !defined(lint)
-__RCSID("$NetBSD: rumpfiber.c,v 1.5 2014/11/05 01:39:40 pooka Exp $");
+__RCSID("$NetBSD: rumpfiber.c,v 1.6 2014/11/08 21:27:04 justin Exp $");
 #endif /* !lint */
 
 #include <sys/ioctl.h>
@@ -199,11 +199,16 @@ create_thread(const char *name, void *cookie, void (*f)(void *), void *data,
 {
 	struct thread *thread = calloc(1, sizeof(struct thread));
 
+	if (!thread) {
+		return NULL;
+	}
+
 	if (!stack) {
 		assert(stack_size == 0);
 		stack = mmap(NULL, STACKSIZE, PROT_READ | PROT_WRITE,
 		    MAP_SHARED | MAP_ANON, -1, 0);
 		if (stack == MAP_FAILED) {
+			free(thread);
 			return NULL;
 		}
 		stack_size = STACKSIZE;