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From:   Andrey Konovalov <andreyknvl@gmail.com>
Date:   Mon, 23 Oct 2023 18:16:42 +0200
Message-ID: <CA+fCnZfDRx6VMSevQKfYYwCj49iqsKMaPaWt95rug-nw8Pgx8w@mail.gmail.com>
Subject: Re: [PATCH v2 11/19] lib/stackdepot: use read/write lock
To:     Alexander Potapenko <glider@google.com>
Cc:     andrey.konovalov@linux.dev, Marco Elver <elver@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vlastimil Babka <vbabka@suse.cz>, kasan-dev@googlegroups.com,
        Evgenii Stepanov <eugenis@google.com>,
        Oscar Salvador <osalvador@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Andrey Konovalov <andreyknvl@google.com>
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On Mon, Oct 9, 2023 at 11:45=E2=80=AFAM Alexander Potapenko <glider@google.=
com> wrote:
>
> >  static struct stack_record *depot_fetch_stack(depot_stack_handle_t han=
dle)
> >  {
> >         union handle_parts parts =3D { .handle =3D handle };
> > -       /*
> > -        * READ_ONCE pairs with potential concurrent write in
> > -        * depot_init_pool.
> > -        */
> > -       int pools_num_cached =3D READ_ONCE(pools_num);
> >         void *pool;
> >         size_t offset =3D parts.offset << DEPOT_STACK_ALIGN;
> >         struct stack_record *stack;
> >
> > -       if (parts.pool_index > pools_num_cached) {
> > +       lockdep_assert_held(&pool_rwlock);
>
> Shouldn't it be lockdep_assert_held_read()?

Indeed, this is more precise. Will fix in v3, thanks!