On Fri, Mar 12, 2021 at 12:02 PM Marco Elver <elver@xxxxxxxxxx> wrote:
>
> On Thu, Mar 11, 2021 at 10:37PM +0100, Andrey Konovalov wrote:
> [...]
> > +Other parts of the kernel might access metadata for allocated objects. Normally,
> > +KASAN detects and reports such accesses, but in certain cases (e.g., in memory
> > +allocators) these accesses are valid. Disabling instrumentation for memory
> > +allocators files helps with accesses that happen directly in that code for
> > +software KASAN modes. But it does not help when the accesses happen indirectly
> > +(through generic function calls) or with the hardware tag-based mode that does
> > +not use compiler instrumentation.
> > +
> > +To disable KASAN reports in a certain part of the kernel code:
> > +
> > +- For software modes, add a
> > + ``kasan_disable_current()``/``kasan_enable_current()`` critical section.
>
> Should we mention function attribute __no_sanitize_address (and noinstr,
> which just applies to any kind of instrumentation) here? Perhaps with
> the note that called functions may still be instrumented, and in such
> cases would require combining with kasan_{disable,enable}_current().
Indeed, forgot about the attributes.. Will add, thank you!
