Re: [PATCH 4/4] mm/kasan: make kasan=on|off take effect for all three modes

Baoquan He
2025-08-08T16:00:02Z

On 08/06/25 at 11:24pm, Sabyrzhan Tasbolatov wrote:
> On Tue, Aug 5, 2025 at 11:34 AM Baoquan He <bhe@redhat.com> wrote:
> >
> > Now everything is ready, set kasan=off can disable kasan for all
> > three modes.
> >
>
> Hello,
>
> I've been working on this already and a different approach
> with the Kconfig ARCH_DEFER_KASAN has been proposed.

Thanks for telling, I don't always watch MM mailing list, so missed your
earlier posting.

I went through your v5 series, we are doing different work. I am adding
kasan=on|off to generic/sw_tags, and have added kasan_enabled() to needed
places. In fact, based on this patchset, we can remove
kasan_arch_is_ready() more easily since in all places kasan_enabled() has
been added there. Before seeing your patches, this is what I planned to
do to remove kasan_arch_is_ready(). I will see what can be done better.
Maybe I can carry your patch in v2. I will try tomorrow.

>
> Please see v4 thread.
> https://lore.kernel.org/all/20250805142622.560992-1-snovitoll@gmail.com/
>
> It also covers the printing in a single KASAN codebase, instead of
> printing "KASAN intiilaized" in arch/* code.
> Also covers the enabling KASAN via kasan_enable() for all 3 modes.
>
> It's up to KASAN maintainers to choose either version.
> I just need the confirmation now if I should proceed with v5,
> or your version if it covers all arch and cases should be picked up.
>
> Thanks
>
> > Signed-off-by: Baoquan He <bhe@redhat.com>
> > ---
> > include/linux/kasan-enabled.h | 11 +----------
> > 1 file changed, 1 insertion(+), 10 deletions(-)
> >
> > diff --git a/include/linux/kasan-enabled.h b/include/linux/kasan-enabled.h
> > index 32f2d19f599f..b5857e15ef14 100644
> > --- a/include/linux/kasan-enabled.h
> > +++ b/include/linux/kasan-enabled.h
> > @@ -8,30 +8,21 @@ extern bool kasan_arg_disabled;
> >
> > DECLARE_STATIC_KEY_FALSE(kasan_flag_enabled);
> >
> > -#ifdef CONFIG_KASAN_HW_TAGS
> > -
> > static __always_inline bool kasan_enabled(void)
> > {
> > return static_branch_likely(&kasan_flag_enabled);
> > }
> >
> > +#ifdef CONFIG_KASAN_HW_TAGS
> > static inline bool kasan_hw_tags_enabled(void)
> > {
> > return kasan_enabled();
> > }
> > -
> > #else /* CONFIG_KASAN_HW_TAGS */
> > -
> > -static inline bool kasan_enabled(void)
> > -{
> > - return IS_ENABLED(CONFIG_KASAN);
> > -}
> > -
> > static inline bool kasan_hw_tags_enabled(void)
> > {
> > return false;
> > }
> > -
> > #endif /* CONFIG_KASAN_HW_TAGS */
> >
> > #endif /* LINUX_KASAN_ENABLED_H */
> > --
> > 2.41.0
> >
> >
>