[LTP] Migrating the libhugetlbfs/testcases/alloc-instantiate-race.c test

[linuxtestproject.agent@gmail.com]

Hi Samir,

On 2026-05-04, Samir <samir@linux.ibm.com> wrote:
> Migrating the libhugetlbfs/testcases/alloc-instantiate-race.c test

> Signed-off-by: Samir <samir@linux.ibm.com>
> v3: https://lore.kernel.org/all/20250928030721.3537869-1-samir@linux.ibm.com/
> v4: https://lore.kernel.org/ltp/20260317095559.5766-1-samir@linux.ibm.com/
>
> LTP Github CI link: https://github.com/linux-test-project/ltp/pull/1313
> All the checks are passed

Version history references should use the `Link:` tag:

  Link: https://lore.kernel.org/ltp/20260317095559.5766-1-samir@linux.ibm.com/

The `LTP Github CI link:` line and `All the checks are passed` are
free text appearing after `Signed-off-by:` and must be removed.

[...]

> +/*
> + * Copyright (C) 2005-2006 IBM Corporation
> + * Author: David Gibson & Adam Litke
> + */

New file must include the year it was added. Add 2026 to the copyright
range.

> +/*
> + * This test is designed to detect a kernel allocation race introduced

The doc block must open with `/*\` (not `/*`) for LTP's RST toolchain.

[...]

> +#include "tst_safe_pthread.h"
> +#include "hugetlb.h"

Add `#include "tst_test.h"` explicitly, as done in the rest of this
directory.

[...]

> +static int child1, child2, race_type, fd_sync;

`fd_sync` zero-initializes to 0 (stdin). `cleanup()` checks
`if (fd_sync >= 0)` and would close stdin if called before `run_test()`.
Also, after `run_test()` calls `SAFE_CLOSE(fd_sync)` without resetting
it to -1, `cleanup()` double-closes the same fd on the normal exit path.
Initialize `fd_sync = -1` and reset it to -1 after each close.

[...]

Pre-existing issues noticed in the surrounding code (not introduced
by this patch):

- run_test(): local `p_sync` (MMAP) is not reachable from cleanup(); leaks if tst_brk() fires inside run_race().
- run_race(): local `fd` and `p` are not reachable from cleanup(); same concern.

---
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