Re: [PATCH 5/6] perf/core: Use ioctl to communicate driver configuration to kernel

[Jiri Olsa]

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