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

Madhavan T. Venkataraman
2022-06-24T05:29:03Z

On 6/24/22 00:19, 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.

Sorry. What I wanted to say was that in v15 I have removed the patch titled:

arm64: Select HAVE_RELIABLE_STACKTRACE

since objtool changes are not in place.

Apologies.

Madhavan

>
> 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.
>
> I can drop patches 4 thru 6. Actually, the objtool patch series that I have
> sent separately for supporting livepatch already addresses reliability. So, if that
> gets reviewed and accepted, we don't even need patches 4 thru 6.
>
> If you are OK with that, I can resend v16 with just patches 1 thru 3. Let me know.
>
> Madhavan