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Date:   Sat, 8 Jul 2023 16:02:47 -0600
From:   Daniel Xu <dxu@dxuuu.xyz>
To:     Leon Hwang <hffilwlqm@gmail.com>
Cc:     ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
        andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
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        jolsa@kernel.org, davem@davemloft.net, edumazet@google.com,
        kuba@kernel.org, pabeni@redhat.com, hawk@kernel.org,
        tangyeechou@gmail.com, kernel-patches-bot@fb.com,
        bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
        netdev@vger.kernel.org
Subject: Re: [PATCH bpf-next v2 0/2] bpf: Introduce user log
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References: <20230708040750.72570-1-hffilwlqm@gmail.com>
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Hi Leon,

On Sat, Jul 08, 2023 at 12:07:48PM +0800, Leon Hwang wrote:
> This series introduces bpf user log to transfer error message from
> kernel space to user space when users provide buffer to receive the
> error message.
> 
> Especially, when to attach XDP to device, it can transfer the error
> message along with errno from dev_xdp_attach() to user space, if error
> happens in dev_xdp_attach().

Have you considered adding a tracepoint instead? With some TP_printk()
stuff I think you can achieve a similar result without having to do
go through changing uapi.

> 
> Leon Hwang (2):
>   bpf: Introduce bpf generic log
>   bpf: Introduce bpf user log
> 
>  include/linux/bpf.h            |  3 ++
>  include/uapi/linux/bpf.h       |  8 ++++++
>  kernel/bpf/log.c               | 52 ++++++++++++++++++++++++++++++++++
>  net/core/dev.c                 |  4 ++-
>  tools/include/uapi/linux/bpf.h |  8 ++++++
>  5 files changed, 74 insertions(+), 1 deletion(-)
> 
> 
> base-commit: 622f876ab3ced325fe3c2363c6e9c128b7e6c73a
> -- 
> 2.41.0
> 
> 

Thanks,
Daniel