Re: [PATCH net-net] tun: Assign missing bpf_net_context.

[Breno Leitao]

Hello Vadim,

On Thu, Sep 12, 2024 at 02:32:55PM +0100, Vadim Fedorenko wrote:
> On 12/09/2024 14:17, Breno Leitao wrote:
> > @@ -72,6 +73,7 @@ static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev)
> >   	struct net_device *peer;
> >   	int len = skb->len;
> > +	bpf_net_ctx = bpf_net_ctx_set(&__bpf_net_ctx);
> >   	rcu_read_lock();
> 
> Hi Breno,
> 
> looks like bpf_net_ctx should be set under rcu read lock...

Why exactly?

I saw in some examples where bpf_net_ctx_set() was set inside the
rcu_read_lock(), but, I was not able to come up with justification to do
the same. Would you mind elaborating why this might be needed inside the
lock?

Thanks for the review,
--breno