netdev - Re: [PATCH] af_packet: Fix softirq mismatch in tpacket

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Message-ID: <05371e60-fe62-4499-b640-11c0635a5186@kernel.org>
Date: Thu, 19 Sep 2024 14:00:38 -0600
From: David Ahern <dsahern@...nel.org>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>,
 Ben Greear <greearb@...delatech.com>, netdev@...r.kernel.org,
 Ido Schimmel <idosch@...dia.com>
Subject: Re: [PATCH] af_packet: Fix softirq mismatch in tpacket_rcv

On 9/19/24 10:44 AM, Willem de Bruijn wrote:
> Yes, it seems that VRF calls dev_queue_xmit_nit without the same BH
> protections that it expects.
> 
> I suspect that the fix is in VRF, to disable BH the same way that
> __dev_queue_xmit does, before calling dev_queue_xmit_nit.
> 

commit 504fc6f4f7f681d2a03aa5f68aad549d90eab853 removed the bh around
dev_queue_xmit_nit:

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index 6043e63b42f9..43f374444684 100644
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -638,9 +638,7 @@ static void vrf_finish_direct(struct sk_buff *skb)
                eth_zero_addr(eth->h_dest);
                eth->h_proto = skb->protocol;

-               rcu_read_lock_bh();
                dev_queue_xmit_nit(skb, vrf_dev);
-               rcu_read_unlock_bh();

                skb_pull(skb, ETH_HLEN);
        }