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From:   Andrey Konovalov <andreyknvl@gmail.com>
Date:   Tue, 10 May 2022 19:20:20 +0200
Message-ID: <CA+fCnZcCOFR-E_HFjgpz1GqPbtnothC1+cTK6Nu2fOua_1-iuQ@mail.gmail.com>
Subject: Re: [PATCH 3/3] kasan: clean-up kconfig options descriptions
To:     Marco Elver <elver@google.com>
Cc:     andrey.konovalov@linux.dev,
        Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        kasan-dev <kasan-dev@googlegroups.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrey Konovalov <andreyknvl@google.com>
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On Tue, May 10, 2022 at 1:57 PM Marco Elver <elver@google.com> wrote:
>
> > -       Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
> > -       (the resulting kernel does not boot).
> > +       (Incompatible with CONFIG_DEBUG_SLAB: the kernel does not boot.)
>
> Why aren't they made mutually exclusive via Kconfig constraints? Does it
> work these days?
>
> Either KASAN_GENERIC and KASAN_SW_TAGS do "depends on !DEBUG_SLAB ||
> COMPILE_TEST", or DEBUG_SLAB does "depends on !(KASAN_GENERIC || KASAN_SW_TAGS) || COMPILE_TEST".
>
> I feel DEBUG_SLAB might not be used very much these days, so perhaps
> DEBUG_SLAB should add the constraint, also given KASAN is the better
> debugging aid.

They are made exclusive: it's the KASAN option that depends on
!DEBUG_SLAB. And KASAN_HW_TAGS doesn't have this note, as it doesn't
work with SLAB at all at the moment. Moving the constraint to
DEBUG_SLAB might make sense, but let's keep this patchset as a
non-functional change. Thanks!