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References: <20221206145936.922196-1-benjamin.tissoires@redhat.com> <20221206145936.922196-2-benjamin.tissoires@redhat.com>
In-Reply-To: <20221206145936.922196-2-benjamin.tissoires@redhat.com>
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Tue, 6 Dec 2022 12:47:47 -0800
Message-ID: <CAADnVQKTQMo3wvJWajQSgT5fTsH-rNsz1z8n9yeM3fx+015-jA@mail.gmail.com>
Subject: Re: [PATCH HID for-next v3 1/5] bpf: do not rely on
 ALLOW_ERROR_INJECTION for fmod_ret
To:     Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc:     Jiri Kosina <jikos@kernel.org>,
        Florent Revest <revest@chromium.org>,
        Jon Hunter <jonathanh@nvidia.com>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>, bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Tue, Dec 6, 2022 at 6:59 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> The current way of expressing that a non-bpf kernel component is willing
> to accept that bpf programs can be attached to it and that they can change
> the return value is to abuse ALLOW_ERROR_INJECTION.
> This is debated in the link below, and the result is that it is not a
> reasonable thing to do.
>
> Reuse the kfunc declaration structure to also tag the kernel functions
> we want to be fmodret. This way we can control from any subsystem which
> functions are being modified by bpf without touching the verifier.
>
>
> Link: https://lore.kernel.org/all/20221121104403.1545f9b5@gandalf.local.home/
> Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
> Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

BPF CI couldn't do its job because of a merge conflict.
CI only tries to apply the whole series.
But I tested the patch 1 manually.
Everything is green on x86-64 and the patch looks good.

Acked-by: Alexei Starovoitov <ast@kernel.org>

Please send the set during the merge window.
If not we can take just this patch,
since the series from Viktor Malik would need this patch too.