[LTP] [PATCH v3 5/9] syscalls: Add epoll_wait10

Petr Vorel pvorel@suse.cz
Fri Jul 10 08:55:56 CEST 2026


Hi Cyril,

> +/*\
> + * Verify that :manpage:epoll_wait() with EPOLLPRI detects changes to
> + * /proc/mounts.
> + *
> + * The kernel generates a poll notification (POLLPRI/EPOLLERR) on
> + * /proc/mounts whenever the mount namespace changes. This test verifies
> + * that epoll can observe these notifications.
> + *
> + * [Algorithm]
> + *
> + * - Open /proc/mounts and register it with an epoll instance for EPOLLPRI.
> + * - Fork a child that mounts and then unmounts a tmpfs filesystem, using
> + *   checkpoints to synchronize with the parent.
> + * - After each mount namespace change the parent calls epoll_wait and verifies
> + *   it returns an event.
> + *
> + * Needs root to call mount/umount.
> + */

Nice test, thanks for the description.
Reviewed-by: Petr Vorel <pvorel@suse.cz>

...
> +static struct tst_test test = {
> +	.test_all = run,
> +	.setup = setup,
> +	.cleanup = cleanup,
> +	.needs_root = 1,
> +	.forks_child = 1,
> +	.needs_checkpoints = 1,
> +	.needs_tmpdir = 1,
Shouldn't we have .needs_kconfigs CONFIG_TMPFS=y
I know it's really a corner case when somebody disable it.

Kind regards,
Petr


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