linux-kernel - Re: [PATCH net-next 0/4] (no cover subject)

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Message-ID: <snoxl67npkzfi63l4ndh3d6qvx2lyxthtrwhfnharhf5llrv4j@zhyzxm3tegia>
Date: Tue, 9 Dec 2025 09:46:51 -0800
From: Breno Leitao <leitao@...ian.org>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Petr Mladek <pmladek@...e.com>, Andrew Lunn <andrew+netdev@...n.ch>, 
	"David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
	Paolo Abeni <pabeni@...hat.com>, Shuah Khan <shuah@...nel.org>, Simon Horman <horms@...nel.org>, 
	Jonathan Corbet <corbet@....net>, netdev@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-kselftest@...r.kernel.org, linux-doc@...r.kernel.org, gustavold@...il.com, 
	asantostc@...il.com, calvin@...nvd.org, kernel-team@...a.com, davej@...emonkey.org.uk
Subject: Re: [PATCH net-next 0/4] (no cover subject)

Hello Jakub,

On Tue, Dec 09, 2025 at 04:37:45PM +0900, Jakub Kicinski wrote:
> On Fri, 5 Dec 2025 02:21:08 -0800 Breno Leitao wrote:
> > 1) Have a binary in each machine:
> 
> > 2) Send a ping directly to the console
> 
> > 3) Using per-loglevel patchset.
> 
> > 4) send messages only to netconsole (this patchset)
> 
> I think I was alluding that another option (not saying that it's the
> best but IIUC your requirements it'd be the best fit)):
> 
> 5) Add a keepalive configfs knob, if set to a non-zero value netconsole
> will send an empty (?) message at given interval
> 
>   Pros:
>    - truly does not require a user binary to run periodically, netcons
>      would set a timer in the kernel
>   Cons:
>    - does not provide the arbitrary "console bypass" message
>      functionality

This is a good idea if we change it slightly. What about a "ping"
configfs item that send sit when I touch it?

Something as:

	# echo 1 > /sys/kernel/configs/<target>/ping
	
And it would ping the host with a predefined "ping" message, and nothing
else.

That would work, for my current problem, honestly.

One drawback compared to a more flexible "send_msg" is that I don't have
complete flexibility on the message format. Thus, if I want to pass
extra information such as a Nonce, timestamp, host state, interface
name, health state, it will not be possible, which is fine for now,
given I am NOT planning to use it at this stage.

Thanks for the idea and discussion,
--breno