Re: [PATCH 0/8] unwind, arm64: add sframe unwinder for kernel

Puranjay Mohan
2025-02-13T22:22:11Z

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Song Liu <song@kernel.org> writes:

> On Thu, Feb 13, 2025 at 12:38 AM Puranjay Mohan <puranjay@kernel.org> wrote:
> [...]
>>
>> P.S. - The livepatch doesn't have copy_process() but only copy_signal(),
>> yours had copy_process() somehow.
>
> In my build, copy_signal is inlined to copy_process, unless I add noinline.
> If I do add noinline, the issue will not reproduce.
>
> I tried more combinations. The issue doesn't reproduce if I either
> 1) add noinline to copy_signal, so we are not patching the whole
> copy_process function;
> or
> 2) Switch compiler from gcc 14.2.1 to gcc 11.5.0.
>
> So it appears something in gcc 14.2.1 is causing live patch to fail
> for copy_process().

So, can you test your RFC set (without SFRAME) with gcc 14.2.1, so we
can be sure that it is not a sframe problem?

And about having the .sframe section in the livepatch module, I realised
that this set doesn't include support for reading/using sframe data from
any module(livepatches included), so the patch I added for generating
.sframe in kpatch is irrelevant because it is a no-op with the current setup.

Thanks,
Puranjay

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