Re: [PATCH v15 0/6] arm64: Reorganize the unwinder and implement stack trace reliability checks

Madhavan T. Venkataraman
2022-06-27T05:46:11Z

On 6/26/22 04:18, Mark Rutland wrote:
> On Fri, Jun 24, 2022 at 12:19:01AM -0500, Madhavan T. Venkataraman wrote:
>>
>>
>> On 6/23/22 12:32, Will Deacon wrote:
>>> On Fri, Jun 17, 2022 at 04:07:11PM -0500, madvenka@linux.microsoft.com wrote:
>>>> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
>>>>
>>>> I have synced this patch series to v5.19-rc2.
>>>> I have also removed the following patch.
>>>>
>>>> [PATCH v14 7/7] arm64: Select HAVE_RELIABLE_STACKTRACE
>>>>
>>>> as HAVE_RELIABLE_STACKTRACE depends on STACK_VALIDATION which is not present
>>>> yet. This patch will be added in the future once Objtool is enhanced to
>>>> provide stack validation in some form.
>>>
>>> Given that it's not at all obvious that we're going to end up using objtool
>>> for arm64, does this patch series gain us anything in isolation?
>>>
>>
>> BTW, I have synced my patchset to 5.19-rc2 and sent it as v15.
>>
>> So, to answer your question, patches 1 thru 3 in v15 are still useful even if we don't
>> consider reliable stacktrace. These patches reorganize the unwinder code based on
>> comments from both Mark Rutland and Mark Brown. Mark Brown has already OKed them.
>> If Mark Rutland OKes them, we should upstream them.
>
> Sorry for the delay; I have been rather swamped recently and haven't had the
> time to give this the time it needs.
>
> I'm happy with patches 1 and 2, and I've acked those in case Will wants to pick
> them.
>
> Kalesh (cc'd) is working to share the unwinder code with hyp, and I think that
> we need to take a step back and consider how we can make the design work
> cleanly with that. I'd had a go at prototyping making the unwinder more data
> driven, but I haven't come up with something satisfactory so far.
>
> It would be good if you could look at / comment on each others series.
>

I will review Kalesh's unwinder changes.

Thanks.

Madhavan