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Re: [PATCH] Revert Intel CET changes to __jmp_buf_tag (Bug 22743)
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?
> You checked these patches in without consensus, and instead of waiting
> or pinging for review, you checked them in.
>
> For x86_64 there is no machine maintainer, it requires community consensus,
Do we need/want machine maintainers for x86-64 (i386)?
> the port is too important not to get serious community review.
>
> They changes had negative ABI consequences, and now you have several
> people interested in making sure future patches don't break ABI.
There are no arguments here.
> You have drawn attention to this work and now you have to reach consensus
> on a solution for a primary architecture which is very important to all of
> us in the downstream distributions. More time is required to make these
> patches work.
>
> I see no clear argument for why this needs to be in 2.27.
That is fine with me.
> I will be reverting the patches in the next 8 hours.
We need this on master so that we can work on CET support.
--
H.J.