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

Madhavan T. Venkataraman
2022-06-27T17:07:35Z

On 6/27/22 11:32, Kalesh Singh wrote:
> On Sun, Jun 26, 2022 at 9:33 PM Madhavan T. Venkataraman
> <madvenka@linux.microsoft.com> wrote:
>>
>>
>>
>> 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 Mark, I'll take a look.
>
> Madhavan, I'm in the process of preparing a new version. Let me rebase
> on your first 2 patches and resend, so you can look at that version
> instead.
>

Sure thing.

Thanks.

Madhavan