netdev - Re: [PATCH net-next,v2 00/16] Netfilter updates for net-next

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Message-ID: <aSjHx34ENi4THN56@strlen.de>
Date: Thu, 27 Nov 2025 22:51:03 +0100
From: Florian Westphal <fw@...len.de>
To: Fernando Fernandez Mancera <fmancera@...e.de>
Cc: Paolo Abeni <pabeni@...hat.com>,
	Pablo Neira Ayuso <pablo@...filter.org>,
	netfilter-devel@...r.kernel.org, davem@...emloft.net,
	netdev@...r.kernel.org, kuba@...nel.org, edumazet@...gle.com,
	horms@...nel.org
Subject: Re: [PATCH net-next,v2 00/16] Netfilter updates for net-next

Fernando Fernandez Mancera <fmancera@...e.de> wrote:
> Patch 12 - I think that should be fine, nf_conncount_tree_skb() which 
> calls count_tree() should called with RCU read lock. This patch didn't 
> modify that behavior.

It would be better to add a READ_ONCE() however, since there can be
a concurrent update.

Not caused by your patch, so future fixup is fine.

> Patch 13 - as we are holding the commit mutex I thought that it wasn't 
> needed. Anyway, if that is needed, there are other places where we have 
> similar issues that would require a fix too. I can follow up on nf tree.

It would be better to add WRITE_ONCE() for both, given we could also be
interrupted on same cpu here.

Yes, the various .update callbacks have similar problematic patterns,
they all should be fixed up if possible.