netdev - Re: [net-next PATCH] net: rcu lock and preempt disable missing around generic xdp

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Message-Id: <20170818.160459.1790177371740031034.davem@davemloft.net>
Date:   Fri, 18 Aug 2017 16:04:59 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     john.fastabend@...il.com
Cc:     daniel@...earbox.net, netdev@...r.kernel.org
Subject: Re: [net-next PATCH] net: rcu lock and preempt disable missing
 around generic xdp

From: John Fastabend <john.fastabend@...il.com>
Date: Wed, 16 Aug 2017 11:33:19 -0700

> do_xdp_generic must be called inside rcu critical section with preempt
> disabled to ensure BPF programs are valid and per-cpu variables used
> for redirect operations are consistent. This patch ensures this is true
> and fixes the splat below.
> 
> The netif_receive_skb_internal() code path is now broken into two rcu
> critical sections. I decided it was better to limit the preempt_enable/disable
> block to just the xdp static key portion and the fallout is more
> rcu_read_lock/unlock calls. Seems like the best option to me.
 ...
> Fixes: d445516966dc ("net: xdp: support xdp generic on virtual devices")
> Fixes: b5cdae3291f7 ("net: Generic XDP")
> Signed-off-by: John Fastabend <john.fastabend@...il.com>

John you'll need to respin this as these code blocks have changed.