From: Alexei Starovoitov <ast@plumgrid.com>
To: Daniel Borkmann <daniel@iogearbox.net>, davem@davemloft.net
Cc: netdev@vger.kernel.org
Subject: Re: [PATCH net-next] ebpf: remove self-assignment in interpreter's tail call
Date: Mon, 13 Jul 2015 11:53:59 -0700 [thread overview]
Message-ID: <55A40947.2000706@plumgrid.com> (raw)
In-Reply-To: <6586042063b52e17a355fce15460ee16c1ee95bf.1436812762.git.daniel@iogearbox.net>
On 7/13/15 11:49 AM, Daniel Borkmann wrote:
> ARG1 = BPF_R1 as it stands, evaluates to regs[BPF_REG_1] = regs[BPF_REG_1]
> and thus has no effect. Add a comment instead, explaining what happens and
> why it's okay to just remove it. Since from user space side, a tail call is
> invoked as a pseudo helper function via bpf_tail_call_proto, the verifier
> checks the arguments just like with any other helper function and makes
> sure that the first argument (regs[BPF_REG_1])'s type is ARG_PTR_TO_CTX.
>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Thanks!
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
next prev parent reply other threads:[~2015-07-13 18:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-13 18:49 [PATCH net-next] ebpf: remove self-assignment in interpreter's tail call Daniel Borkmann
2015-07-13 18:53 ` Alexei Starovoitov [this message]
2015-07-13 20:12 ` David Miller
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