netdev - Re: [PATCH bpf-next v3 1/2] bpf: clean-up bpf_verifier_vlog() for BPF_LOG

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Message-ID: <9537f384-121b-744b-cdfd-0a3df0fc713e@fb.com>
Date:   Tue, 2 Nov 2021 10:27:03 -0700
From:   Yonghong Song <yhs@...com>
To:     Hou Tao <houtao1@...wei.com>, Alexei Starovoitov <ast@...nel.org>
CC:     Martin KaFai Lau <kafai@...com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>, <netdev@...r.kernel.org>,
        <bpf@...r.kernel.org>
Subject: Re: [PATCH bpf-next v3 1/2] bpf: clean-up bpf_verifier_vlog() for
 BPF_LOG_KERNEL log level



On 11/2/21 3:15 AM, Hou Tao wrote:
> An extra newline will output for bpf_log() with BPF_LOG_KERNEL level
> as shown below:
> 
> [   52.095704] BPF:The function test_3 has 12 arguments. Too many.
> [   52.095704]
> [   52.096896] Error in parsing func ptr test_3 in struct bpf_dummy_ops
> 
> Now all bpf_log() are ended by newline, but not all btf_verifier_log()
> are ended by newline, so checking whether or not the log message
> has the trailing newline and adding a newline if not.
> 
> Also there is no need to calculate the left userspace buffer size
> for kernel log output and to truncate the output by '\0' which
> has already been done by vscnprintf(), so only do these for
> userspace log output.
> 
> Signed-off-by: Hou Tao <houtao1@...wei.com>

Acked-by: Yonghong Song <yhs@...com>