Re: [PATCH v3 00/12] mm/kasan: make kasan=on|off work for all three modes

Andrey Konovalov
2025-09-23T17:49:59Z

On Mon, Sep 15, 2025 at 11:05 AM Baoquan He <bhe@redhat.com> wrote:
>
> > If you feel strongly that the ~1/8th RAM overhead (coming from the
> > physmap shadow and the slab redzones) is still unacceptable for your
> > use case (noting that the performance overhead (and the constant
> > silent detection of false-positive bugs) would still be there), I
> > think you can proceed with your series (unless someone else is
> > against).
>
> Yeah, that would be great if we can also avoid any not needed memory
> consumption for kdump.

Ack. Let's add support for kasan=off then.

But please describe it in detail in the KASAN documentation.

[...]

> When I made patch and posted, I didn't see Sabyrzhan's patches because I
> usually don't go through mm mailing list. If I saw his patch earlier, I
> would have suggested him to solve this at the same time.
>
> About Sabyrzhan's patch sereis, I have picked up part of his patches and
> credit the author to Sabyrzhan in below patchset.
>
> [PATCH 0/4] mm/kasan: remove kasan_arch_is_ready()
> https://lore.kernel.org/all/20250812130933.71593-1-bhe@redhat.com/T/#u
>
> About reposting of this series, do you think which one is preferred:
>
> 1) Firstly merge Sabyrzhan's patch series, I reverted them and apply for
> my patchset.
>
> 2) Credit the author of patch 1,2,3 of this patch series to Sabyrzhan
> too as below, because Sabyrzhan do the unification of the static keys
> usage and the KASAN initialization calls earlier:

Since the Sabyrzhan's patches are already in mm-stable (and I assume
will be merged during the next merge window), just rebase your changes
on top.

But also note that Sabyrzhan is planning to move out the
kasan_enabled() checks into include/linux/kasan.h (which is a clean-up
I would have also asked you to do with the kasan=off patches), so
maybe you should sync up with him wrt these changes.

Thanks!