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Message-ID: <b7bca44c-d562-8894-7de3-a6686e1052fa@linux.microsoft.com>
Date:   Fri, 24 Jun 2022 00:27:58 -0500
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Subject: Re: [PATCH v15 0/6] arm64: Reorganize the unwinder and implement
 stack trace reliability checks
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From:   "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
To:     Will Deacon <will@kernel.org>
Cc:     broonie@kernel.org, mark.rutland@arm.com, jpoimboe@redhat.com,
        ardb@kernel.org, nobuta.keiya@fujitsu.com,
        sjitindarsingh@gmail.com, catalin.marinas@arm.com,
        jamorris@linux.microsoft.com, linux-arm-kernel@lists.infradead.org,
        live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
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 <20220617210717.27126-1-madvenka@linux.microsoft.com>
 <20220623173224.GB16966@willie-the-truck>
 <66545c21-cfcf-60eb-4acf-39be99520369@linux.microsoft.com>
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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
>