[LTP] syscalls/fanotify26: Add test for nested permission events

[Edvard Conrad]

Hi,

On Wed, Oct 28, 2026 at 09:15:42AM +0000, linuxtestproject.agent wrote:
> Since the test is added to runtest/staging for an unreleased kernel fix,
> the commit subject must include the [STAGING] prefix:
>
>     [STAGING] syscalls/fanotify26: Add test for nested permission events

ground_rules.rst asks for the keyword in the patch subject, and gives

  Subject: [PATCH v1][STAGING] fanotify: add test for <feature> (requires v6.19-rc3)

as the example. The mail went out as "[PATCH v2][STAGING] syscalls/fanotify26:
..." and the archive shows it arrived that way. fanotify23, the last test added
to runtest/staging in a8cd03037, likewise carries no [STAGING] in its commit
subject, so I have left the commit subject alone.

> Please use SAFE_READ_ALL instead of the literal 1, matching
> SAFE_WRITE_ALL below:

Done in v3.

> This SAFE_WAITPID() is redundant and discards the child's exit status.
> The test library calls tst_reap_children() automatically after each
> run() iteration [...]

Right, and dropped in v3 for the opener.

Worth noting it does not generalise to the other child: the reader is killed
with SIGKILL on the failure path, and check_child_status() reports TBROK for a
signal-killed child, so that one still has to be reaped by the test itself.

Thanks for the review.

Edvard