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Re: [PATCH v2] Remove signal handling for nanosleep (bug 16364)
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: Florian Weimer <fweimer at redhat dot com>, Andreas Schwab <schwab at suse dot de>
- Cc: libc-alpha at sourceware dot org, Adhemerval Zanella <adhemerval dot zanella at linaro dot com>
- Date: Tue, 17 Nov 2015 12:08:50 -0200
- Subject: Re: [PATCH v2] Remove signal handling for nanosleep (bug 16364)
- Authentication-results: sourceware.org; auth=none
- References: <1447160038-11754-1-git-send-email-adhemerval dot zanella at linaro dot org> <mvmy4e6yoxv dot fsf at hawking dot suse dot de> <5641F136 dot 9030204 at linaro dot org> <mvmtwouylw0 dot fsf at hawking dot suse dot de> <56422DD1 dot 3070406 at redhat dot com> <5643379F dot 3020604 at linaro dot org>
On 11-11-2015 10:42, Adhemerval Zanella wrote:
>
>
> On 10-11-2015 15:48, Florian Weimer wrote:
>> On 11/10/2015 03:22 PM, Andreas Schwab wrote:
>>> Adhemerval Zanella <adhemerval.zanella@linaro.org> writes:
>>>
>>>> That's the hole points of the previous discussion in v1 patch while
>>>> Florian also pointed this racy. He neither I could devise a race-free
>>>> testcase to check for this issue so my questioning was if someone have
>>>> a way to remove the race or if we really should push for this test.
>>>
>>> A racy test is as good as a non-existing test. Everyone will ignore it.
>>
>> I disagree very strongly. It depends on the frequency of the race, and
>> it which direction it errs (FAIL even without the bug, or PASS with the
>> bug). Some properties are impossible to test without theoretic races.
>> It really depends on the rate of inappropriate FAILs whether such tests
>> have value or not.
>
> Regarding to this specific test, IMHO I would prefer to not add it since
> it clearly a kernel issue which has been fixed in a long time and it is
> quite unlike to regress. Also, any regression would be flagged a kernel
> defect and I do not see this being deployed in any kernel release.
>
> Now regarding the racy test, I see we need to assess by case basis. I
> also I do not see strong reasoning to block this patch altogether: we
> can evaluate/push the version v3 which do not have the testcase and
> if we decide this race-test is valuable I can prepare another patch
> to add it.
It appears this discussion has been stalled and to move forward at least
with the patch core discussion (nanosleep refactor), I would like to
continue discuss solely the code modification at its third version [1].
I will send another patch with the only the testcase and then we can
continue discuss if it worth or not to include possible racy testcase
in GLIBC.
[1] https://sourceware.org/ml/libc-alpha/2015-11/msg00206.html
>
>>
>> Florian
>>