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From:   Marco Elver <elver@google.com>
Date:   Mon, 7 Mar 2022 00:52:48 +0100
Message-ID: <CANpmjNM+47dfjLyyuQwUWZyJgsr1Uxd72VPe9Vva3Qr2oiXRHA@mail.gmail.com>
Subject: Re: [PATCH v2 2/2] kfence: Alloc kfence_pool after system startup
To:     Tianchen Ding <dtcccc@linux.alibaba.com>
Cc:     Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        kasan-dev@googlegroups.com, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
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On Sat, 5 Mar 2022 at 15:49, Tianchen Ding <dtcccc@linux.alibaba.com> wrote=
:
[...]
> +static int kfence_init_late(void)
> +{
> +       const unsigned long nr_pages =3D KFENCE_POOL_SIZE / PAGE_SIZE;
> +       struct page *pages;
> +
> +       pages =3D alloc_contig_pages(nr_pages, GFP_KERNEL, first_online_n=
ode, NULL);

> mm/kfence/core.c:836:17: error: implicit declaration of function =E2=80=
=98alloc_contig_pages=E2=80=99 [-Werror=3Dimplicit-function-declaration]

This doesn't build without CMA. See ifdef CONFIG_CONTIG_ALLOC in
gfp.h, which declares alloc_contig_pages.

Will alloc_pages() work as you expect? If so, perhaps only use
alloc_contig_pages() #ifdef CONFIG_CONTIG_ALLOC.

Thanks,
-- Marco