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

[Carlos O'Donell <carlos at redhat dot com>]

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.

-- 
Cheers,
Carlos.