On Mon, Jul 02, 2018 at 04:33:29PM -0600, Mathieu Poirier wrote:

SNIP

+	ret = 0;
+out:
+	return ret;
+}
+
+static int perf_event_set_drv_config(struct perf_event *event, void __user *arg)
+{
+	int ret = -EINVAL;
+	char *config_str;
+
+	config_str = strndup_user(arg, PAGE_SIZE);
+	if (IS_ERR(config_str))
+		return PTR_ERR(config_str);
+
+	if (has_drv_config(event))

would it be better to make this check before
the alloc/copy data from user takes place?

jirka