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From:   KP Singh <kpsingh@kernel.org>
Date:   Tue, 12 Jan 2021 14:57:34 +0100
Message-ID: <CACYkzJ6DJ0NEm+qTBpMSJNFfgNHBFPZc=Ytj4w+4hY=Co4=0yg@mail.gmail.com>
Subject: Re: [PATCH bpf 1/2] bpf: support PTR_TO_MEM{,_OR_NULL} register spilling
To:     Gilad Reti <gilad.reti@gmail.com>
Cc:     bpf <bpf@vger.kernel.org>, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        Networking <netdev@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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On Tue, Jan 12, 2021 at 10:14 AM Gilad Reti <gilad.reti@gmail.com> wrote:
>
> Add support for pointer to mem register spilling, to allow the verifier
> to track pointer to valid memory addresses. Such pointers are returned

nit: pointers

> for example by a successful call of the bpf_ringbuf_reserve helper.
>
> This patch was suggested as a solution by Yonghong Song.

You can use the "Suggested-by:" tag for this.

>
> The patch was partially contibuted by CyberArk Software, Inc.

nit: typo *contributed

Also, I was wondering if "partially" here means someone collaborated with you
on the patch? And, in that case:

"Co-developed-by:" would be a better tag here.

Acked-by: KP Singh <kpsingh@kernel.org>


>
> Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier
> support for it")
> Signed-off-by: Gilad Reti <gilad.reti@gmail.com>
> ---
>  kernel/bpf/verifier.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 17270b8404f1..36af69fac591 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -2217,6 +2217,8 @@ static bool is_spillable_regtype(enum bpf_reg_type type)
>         case PTR_TO_RDWR_BUF:
>         case PTR_TO_RDWR_BUF_OR_NULL:
>         case PTR_TO_PERCPU_BTF_ID:
> +       case PTR_TO_MEM:
> +       case PTR_TO_MEM_OR_NULL:
>                 return true;
>         default:
>                 return false;
> --
> 2.27.0
>