Re: [PATCH v5 15/19] kasan: x86: Apply multishot to the inline report handler

[Andrey Konovalov <andreyknvl@gmail.com>]

On Tue, Sep 9, 2025 at 4:45 PM Andrey Konovalov <andreyknvl@gmail.com> wrote:
>
> On Tue, Sep 9, 2025 at 10:42 AM Maciej Wieczor-Retman
> <maciej.wieczor-retman@intel.com> wrote:
> >
> > On 2025-09-08 at 22:19:11 +0200, Andrey Konovalov wrote:
> > >On Mon, Sep 8, 2025 at 3:04 PM Maciej Wieczor-Retman
> > ><maciej.wieczor-retman@intel.com> wrote:
> > >>
> > >> >> +       if (kasan_multi_shot_enabled())
> > >> >> +               return true;
> > >> >
> > >> >It's odd this this is required on x86 but not on arm64, see my comment
> > >> >on the patch that adds kasan_inline_handler().
> > >> >
> > >>
> > >> I think this is needed if we want to keep the kasan_inline_recover below.
> > >> Because without this patch, kasan_report() will report a mismatch, an then die()
> > >> will be called. So the multishot gets ignored.
> > >
> > >But die() should be called only when recovery is disabled. And
> > >recovery should always be enabled.
> >
> > Hmm I thought when I was testing inline mode last time, that recovery was always
> > disabled. I'll recheck later.
> >
> > But just looking at llvm code, hwasan-recover has init(false). And the kernel
> > doesn't do anything to this value in Makefile.kasan. Perhaps it just needs to be
> > corrected in the Makefile.kasan?
>
> Recovery should be disabled as the default when

Eh, enabled, not disabled.

> -fsanitize=kernel-hwaddress is used (unless something was
> broken/changed); see this patch:
>
> https://github.com/llvm/llvm-project/commit/1ba9d9c6ca1ffeef7e833261ebca463a92adf82f