netdev - Re: [PATCH net-next] net: always dump full packets with skb

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Message-ID: <20201006114322.aq276lij2ovhdtts@skbuf>
Date:   Tue, 6 Oct 2020 11:43:23 +0000
From:   Vladimir Oltean <vladimir.oltean@....com>
To:     Willem de Bruijn <willemdebruijn.kernel@...il.com>
CC:     Jacob Keller <jacob.e.keller@...el.com>,
        Network Development <netdev@...r.kernel.org>,
        David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Subject: Re: [PATCH net-next] net: always dump full packets with skb_dump

On Tue, Oct 06, 2020 at 07:30:13AM -0400, Willem de Bruijn wrote:
> skb_dump is called from skb_warn_bad_offload and netdev_rx_csum_fault.
> Previously when these were triggered, a few example bad packets were
> sufficient to debug the issue.

Yes, and it's only netdev_rx_csum_fault that matters, because
skb_warn_bad_offload calls with full_pkt=false anyway.

During the times when I had netdev_rx_csum_fault triggered, it was
pretty bad anyway. I don't think that full_pkt getting unset after 5
skbs made too big of a difference.

> A full dump can add a lot of data to the kernel log, so I limited to
> what is strictly needed.

Yes, well my expectation is that other people are using skb_dump for
debugging, even beyond those 2 callers in the mainline kernel. And when
they want to dump with full_pkt=true, they really want to dump with
full_pkt=true.

Thanks,
-Vladimir