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Date: Wed, 15 May 2024 15:27:38 +0200
From: Florian Westphal <fw@strlen.de>
To: Eric Dumazet <edumazet@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Pablo Neira Ayuso <pablo@netfilter.org>,
	Jozsef Kadlecsik <kadlec@netfilter.org>, netdev@vger.kernel.org,
	netfilter-devel@vger.kernel.org, coreteam@netfilter.org,
	eric.dumazet@gmail.com, syzbot <syzkaller@googlegroups.com>
Subject: Re: [PATCH net] netfilter: nfnetlink_queue: acquire rcu_read_lock()
 in instance_destroy_rcu()
Message-ID: <20240515132738.GD13678@breakpoint.cc>
References: <20240515132339.3346267-1-edumazet@google.com>
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User-Agent: Mutt/1.10.1 (2018-07-13)

Eric Dumazet <edumazet@google.com> wrote:
> diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
> index 00f4bd21c59b419e96794127693c21ccb05e45b0..f1c31757e4969e8f975c7a1ebbc3b96148ec9724 100644
> --- a/net/netfilter/nfnetlink_queue.c
> +++ b/net/netfilter/nfnetlink_queue.c
> @@ -169,7 +169,9 @@ instance_destroy_rcu(struct rcu_head *head)
>  	struct nfqnl_instance *inst = container_of(head, struct nfqnl_instance,
>  						   rcu);
>  
> +	rcu_read_lock();
>  	nfqnl_flush(inst, NULL, 0);
> +	rcu_read_unlock();

That works too.  I sent a different patch for the same issue yesterday:

https://patchwork.ozlabs.org/project/netfilter-devel/patch/20240514103133.2784-1-fw@strlen.de/

If you prefer Erics patch thats absolutely fine with me, I'll rebase in
that case to keep the selftest around.