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References: <20220720114652.3020467-1-asavkov@redhat.com> <20220720114652.3020467-2-asavkov@redhat.com>
In-Reply-To: <20220720114652.3020467-2-asavkov@redhat.com>
From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Thu, 21 Jul 2022 07:02:07 -0700
Message-ID: <CAADnVQ+mt1iEsXUGBeL-dgXRoRwPxoz+G=aRcZTkhx2AA10R-A@mail.gmail.com>
Subject: Re: [PATCH bpf-next 1/4] bpf: add BPF_F_DESTRUCTIVE flag for BPF_PROG_LOAD
To:     Artem Savkov <asavkov@redhat.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>, bpf <bpf@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Daniel Vacek <dvacek@redhat.com>,
        Jiri Olsa <olsajiri@gmail.com>, Song Liu <song@kernel.org>
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On Wed, Jul 20, 2022 at 4:47 AM Artem Savkov <asavkov@redhat.com> wrote:
>
> +/* If BPF_F_DESTRUCTIVE is used in BPF_PROG_LOAD command, the loaded program
> + * will be able to perform destructive operations such as calling bpf_panic()
> + * helper.
> + */
> +#define BPF_F_DESTRUCTIVE      (1U << 6)

I don't understand what value this flag provides.

bpf prog won't be using kexec accidentally.
Requiring user space to also pass this flag seems pointless.