Re: [PATCH v2 3/4] seccomp: add a way to get a listener fd from ptrace

[Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

again, I don't understand this code yet, but

On 05/17, Tycho Andersen wrote:
>
> +long seccomp_get_listener(struct task_struct *task,
> +			  unsigned long filter_off)
> +{
> +	struct seccomp_filter *filter;
> +	struct file *listener;
> +	int fd;
> +
> +	filter = get_nth_filter(task, filter_off);
> +	if (IS_ERR(filter))
> +		return PTR_ERR(filter);
> +
> +	fd = get_unused_fd_flags(O_RDWR);
> +	if (fd < 0) {
> +		__put_seccomp_filter(filter);
> +		return fd;
> +	}
> +
> +	listener = init_listener(task, task->seccomp.filter);
> +	if (IS_ERR(listener)) {
> +		put_unused_fd(fd);
> +		return PTR_ERR(listener);

__put_seccomp_filter() ?

and since init_listener() does __get_seccomp_filter() on sucess, it is needed
uncondtitionally?

Oleg.