diff --git a/sbin/swapon/swapon.c b/sbin/swapon/swapon.c
index ed9f5685b6bc..f58143179c2f 100644
--- a/sbin/swapon/swapon.c
+++ b/sbin/swapon/swapon.c
@@ -642,6 +642,7 @@ run_cmd(int *ofd, const char *cmdline, ...)
 	rv = vasprintf(&cmd, cmdline, ap);
 	if (rv == -1) {
 		warn("%s", __func__);
+		va_end(ap);
 		return (rv);
 	}
 	va_end(ap);