linux-kernel - Re: [PATCH v2 17/19] kasan: remove atomic accesses to stack ring entries

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Message-ID: <CA+fCnZcLL9vapkMv292FnQdxbUY=_q8-r6aQ+9=okjk8ua7JLg@mail.gmail.com>
Date:   Mon, 23 Oct 2023 18:17:26 +0200
From:   Andrey Konovalov <andreyknvl@...il.com>
To:     Alexander Potapenko <glider@...gle.com>
Cc:     andrey.konovalov@...ux.dev, Marco Elver <elver@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>, kasan-dev@...glegroups.com,
        Evgenii Stepanov <eugenis@...gle.com>,
        Oscar Salvador <osalvador@...e.de>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        Andrey Konovalov <andreyknvl@...gle.com>
Subject: Re: [PATCH v2 17/19] kasan: remove atomic accesses to stack ring entries

On Mon, Oct 9, 2023 at 2:05 PM Alexander Potapenko <glider@...gle.com> wrote:
>
> On Wed, Sep 13, 2023 at 7:17 PM <andrey.konovalov@...ux.dev> wrote:
> >
> > From: Andrey Konovalov <andreyknvl@...gle.com>
> >
> > Remove the atomic accesses to entry fields in save_stack_info and
> > kasan_complete_mode_report_info for tag-based KASAN modes.
> >
> > These atomics are not required, as the read/write lock prevents the
> > entries from being read (in kasan_complete_mode_report_info) while being
> > written (in save_stack_info) and the try_cmpxchg prevents the same entry
> > from being rewritten (in save_stack_info) in the unlikely case of wrapping
> > during writing.
>
> Given that you removed all atomic accesses, it should be fine to
> remove the inclusion of atomic.h as well.

Not all of them are removed: stack_ring.pos is still accessed via atomics.

> > Signed-off-by: Andrey Konovalov <andreyknvl@...gle.com>
> Reviewed-by: Alexander Potapenko <glider@...gle.com>

Thanks!