[LTP] cpufreq.c: add new test for cpufreq sysfs interface validation

[linuxtestproject.agent@gmail.com]

Hi Piotr,

On Wed, 6 May 2026, Piotr Kubaj wrote:
> cpufreq.c: add new test for cpufreq sysfs interface validation
>
> Runs various sanity checks for intel_pstate cpufreq sysfs interface.
> [...]

The commit body describes what the test does but not why it is needed.
The motivation ("LTP has no regression coverage for the intel_pstate
cpufreq sysfs interface...") belongs in the commit body, not only in
the in-source doc comment.

> +	fd = SAFE_OPEN(path, O_RDONLY);
> +	SAFE_READ(0, fd, contents, sizeof(contents));
> +	SAFE_CLOSE(fd);

If SAFE_READ fails it calls tst_brk(), skipping SAFE_CLOSE(). cleanup()
has no fd handling so the descriptor leaks. Use SAFE_FILE_SCANF() instead.
This pattern appears twice (~line 184 and ~line 298).

> +static bool setup_done;
[...]
> +	setup_done = true;

setup_done is never reset in cleanup(). With -i, a partial setup failure
on a later iteration sees stale 'true' and incorrectly enters the restore
path. Reset it at the start of setup() or end of cleanup().

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