Re: [PATCH v2 12/32] mm/vmalloc: vmalloc_to_page() use pte_offset_kernel()

Linux regression tracking (Thorsten Leemhuis)
2023-08-08T18:29:34Z

On 20.07.23 14:06, Mark Brown wrote:
> On Thu, Jul 20, 2023 at 11:32:28AM +0100, Will Deacon wrote:
>> On Tue, Jul 11, 2023 at 06:57:33PM +0100, Mark Brown wrote:
>
>>> Still investigating but I'm pretty convinced this is nothing to do with
>>> your commit/series and is just common or garden memory corruption that
>>> just happens to get tickled by your changes. Sorry for the noise.
>
>> Did you get to the bottom of this? If not, do you have a reliable way to
>> reproduce the problem? I don't like the sound of memory corruption :(
>
> Not to the bottom of it, but getting there - I isolated the issue to
> something in the unregistration path for thermal zones but didn't manage
> to figure out exactly what.

Hi Mark, just wondering did anything come out of this and is this still
happening? I'm just wondering, as I still have this on my list of
tracked regressions.

Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
--
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#regzbot poke
> There was some indication it might be a use
> after free but I'm not convinced.
>
> I have a reliable way to reproduce this if you have a pine64plus, it
> also shows up a lot on the Libretech Tritium but not quite so reliably
> as pine64plus since Hugh's changes. Equally pine64plus was rock solid
> until those so there's some timing/environment thing going on which
> makes the issue manifest obviously, I expect you should be able to
> trigger the issue by unregistering a thermal driver but the effects
> might not be visible.
>
> There is a change on the list to make the Allwinner SoCs not trigger the
> issue during boot (their thermal driver refuses to register if any one
> zone fails but most of their SoCs have multiple thermal zones with only
> one fully described) but it needs fixing either way.