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Date: Tue, 19 Dec 2023 15:58:13 +0100
From: Florian Westphal <fw@strlen.de>
To: "D. Wythe" <alibuda@linux.alibaba.com>
Cc: Simon Horman <horms@kernel.org>, pablo@netfilter.org,
	kadlec@netfilter.org, fw@strlen.de, bpf@vger.kernel.org,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
	coreteam@netfilter.org, netfilter-devel@vger.kernel.org,
	davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com, ast@kernel.org
Subject: Re: [RFC nf-next v2 1/2] netfilter: bpf: support prog update
Message-ID: <20231219145813.GA28704@breakpoint.cc>
References: <1702873101-77522-1-git-send-email-alibuda@linux.alibaba.com>
 <1702873101-77522-2-git-send-email-alibuda@linux.alibaba.com>
 <20231218190640.GJ6288@kernel.org>
 <2fd4fb88-8aaa-b22d-d048-776a6c19d9a6@linux.alibaba.com>
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D. Wythe <alibuda@linux.alibaba.com> wrote:
> net/netfilter/nf_bpf_link.c:31:22: note: in expansion of macro
> ‘rcu_dereference’
>    31 |  return bpf_prog_run(rcu_dereference((const struct bpf_prog __rcu
> *)nf_link->link.prog), &ctx);
>       |                      ^~~~~~~~~~~~~~~
> 
> So, I think we might need to go back to version 1.
> 
> @ Florian , what do you think ?

Use rcu_dereference_raw().