Re: [PATCH] selftests/timers/posix_timers: reimplement check_timer_distribution()

From: Thomas Gleixner <tglx@linutronix.de>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	John Stultz <jstultz@google.com>, Marco Elver <elver@google.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	kasan-dev@googlegroups.com, Edward Liaw <edliaw@google.com>,
	Carlos Llamas <cmllamas@google.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] selftests/timers/posix_timers: reimplement check_timer_distribution()
Date: Tue, 09 Apr 2024 14:02:40 +0200	[thread overview]
Message-ID: <877ch67nhb.ffs@tglx> (raw)
In-Reply-To: <20240409111051.GB29396@redhat.com>

On Tue, Apr 09 2024 at 13:10, Oleg Nesterov wrote:
> On 04/09, Thomas Gleixner wrote:
> It seems that this is because in your tree check_timer_distribution() does
>
> 	if (timer_delete(id)) {
> 		ksft_perror("Can't delete timer");
> 		return 0;
> 	}
>
> while in Linus's tree it returns -1 if timer_delete()
> fails. Nevermind.

Ooops.

>> +static bool check_kernel_version(unsigned int min_major, unsigned int min_minor)
>> +{
>> +	unsigned int major, minor;
>> +	struct utsname info;
>> +
>> +	uname(&info);
>> +	if (sscanf(info.release, "%u.%u.", &major, &minor) != 2)
>> +		ksft_exit_fail();
>> +	return major > min_major || (major == min_major && minor >= min_minor);
>> +}
>
> this looks useful regardless. Perhaps it should be moved into
> tools/testing/selftests/kselftest.h as ksft_ck_kernel_version() ?

Makes sense.

>> +static int check_timer_distribution(void)
>> +{
>> +	const char *errmsg;
>> +
>> +	if (!check_kernel_version(6, 3)) {
>> +		ksft_test_result_skip("check signal distribution (old kernel)\n");
>>  		return 0;
>
> ..
>
>> +	ksft_test_result(!ctd_failed, "check signal distribution\n");
>
> Perhaps
>
> 	if (!ctd_failed)
> 		ksft_test_result_pass("check signal distribution\n");
> 	else if (check_kernel_version(6, 3))
> 		ksft_test_result_fail("check signal distribution\n");
> 	else
> 		ksft_test_result_skip("check signal distribution (old kernel)\n");
>
> makes more sense?
>
> This way it can be used on the older kernels with bcb7ee79029d backported.

Indeed.