[LTP] [PATCH] userfaultfd: Add test using UFFDIO_POISON

[Cyril Hrubis]

Hi!
> +static void run(void)
> +{
> +	pthread_t thr;
> +	struct uffdio_api uffdio_api = {};
> +	struct uffdio_register uffdio_register;
> +	struct sigaction sa = {};
> +	volatile char dummy;
> +
> +	sa.sa_handler = sigbus_handler;
> +	sigemptyset(&sa.sa_mask);
> +	SAFE_SIGACTION(SIGBUS, &sa, NULL);
> +
> +	set_pages();
> +
> +	uffd = SAFE_USERFAULTFD(O_CLOEXEC | O_NONBLOCK, false);
> +
> +	uffdio_api.api = UFFD_API;
> +	uffdio_api.features = UFFD_FEATURE_POISON;
> +
> +	SAFE_IOCTL(uffd, UFFDIO_API, &uffdio_api);
> +
> +	uffdio_register.range.start = (unsigned long) page;
> +	uffdio_register.range.len = page_size;
> +	uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
> +
> +	SAFE_IOCTL(uffd, UFFDIO_REGISTER, &uffdio_register);
> +
> +	SAFE_PTHREAD_BARRIER_INIT(&barrier, NULL, 2);

Why does this test need barriers and the rest of the tests that looks
nearly the same does not?

-- 
Cyril Hrubis
chrubis@suse.cz