diff --git a/tools/virtio/ringtest/main.c b/tools/virtio/ringtest/main.c
index f31353fac5415d8b9f5614e6f46f71a8f062f09b..2801ab7547e228a0a0bfd6b88febcc82fe62ce61 100644
--- a/tools/virtio/ringtest/main.c
+++ b/tools/virtio/ringtest/main.c
@@ -86,7 +86,7 @@ void set_affinity(const char *arg)
 	cpu = strtol(arg, &endptr, 0);
 	assert(!*endptr);
 
-	assert(cpu >= 0 || cpu < CPU_SETSIZE);
+	assert(cpu >= 0 && cpu < CPU_SETSIZE);
 
 	self = pthread_self();
 	CPU_ZERO(&cpuset);