Re: [PATCH] Revert Intel CET changes to __jmp_buf_tag (Bug 22743)

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Thu, Jan 25, 2018 at 11:45 PM, Carlos O'Donell <carlos@redhat.com> wrote:
> On 01/25/2018 09:01 AM, H.J. Lu wrote:
>> On Thu, Jan 25, 2018 at 8:46 AM, Carlos O'Donell <carlos@redhat.com> wrote:
>>> On 01/25/2018 08:40 AM, H.J. Lu wrote:
>>>> On Thu, Jan 25, 2018 at 8:36 AM, Carlos O'Donell <carlos@redhat.com> wrote:
>>>>> On 01/25/2018 08:28 AM, H.J. Lu wrote:
>>>>>> On Thu, Jan 25, 2018 at 8:22 AM, Zack Weinberg <zackw@panix.com> wrote:
>>>>>>> On Thu, Jan 25, 2018 at 10:33 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>>>>> On Thu, Jan 25, 2018 at 6:55 AM, Zack Weinberg <zackw@panix.com> wrote:
>>>>>>>>> In my opinion, the fact that you two are having this argument
>>>>>>>>> reinforces Carlos' position: the original patch should be reverted and
>>>>>>>>> we should figure out what to do in 2.28 when we're not under time
>>>>>>>>> pressure.  HJ, do you have some concrete external reason why you must
>>>>>>>>> have this new feature in 2.27?  If so, please tell us what it is.  To
>>>>>>>>> me it doesn't seem urgent.
>>>>>>>>
>>>>>>>> My question is if we are going to fix it at all.  If yes, why not 2.27.
>>>>>>>> Both approaches are opaque to users.  They can't tell the difference.
>>>>>>>
>>>>>>> My concerns are entirely based on timing: specifically, you seem to be
>>>>>>> in a rush to squeak under the 2.27 deadline.  Rushing leads to
>>>>>>> mistakes.
>>>>>>
>>>>>> The main issue for this one is testcase.  Once a testcase is found, we
>>>>>> know how to avoid the issue.
>>>>>>
>>>>>>> This seems like the sort of thing that could reasonably be backported
>>>>>>> to the release branch(es) ... *after* we have calmly, without rushing,
>>>>>>> figured out the correct fix in mainline.
>>>>>>>
>>>>>>
>>>>>> I am fine with reverting my patch only on 2.27 branch, not on master.
>>>>>
>>>>> This does not make sense. The revert on master would last for as long as
>>>>> you have to come up with a patch that works and everyone accepts and has
>>>>> consensus.
>>>>
>>>> We have 2 proposals, one with a patch and one without.  How long
>>>> should it take to make a decision?
>>>
>>> However long it takes.
>>>
>>> Until then we revert the patches.
>>>
>>
>> Sure.  Please revert it now.
>>
>>  I will submit a patch to re-apply it + my fix after 2.27 branch
>> is taken.
>
> I have reverted the ABI breaking changes along with the matching
> change which adds feature_1.
>
> Thank you for working with everyone on this issue. I will spend the
> day tomorrow reviewing these patches.
>

FYI, my current patch is on hjl/pr22743/master branch at

https://github.com/hjl-tools/glibc/tree/hjl/pr22743/master

-- 
H.J.