From: Gal Pressman <gal@nvidia.com>
To: Jakub Kicinski <kuba@kernel.org>, davem@davemloft.net
Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com,
andrew+netdev@lunn.ch, horms@kernel.org, ast@kernel.org,
daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev,
eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me,
haoluo@google.com, jolsa@kernel.org, dsahern@gmail.com,
bpf@vger.kernel.org
Subject: Re: [PATCH net] net: don't touch dev->stats in BPF redirect paths
Date: Thu, 29 Jan 2026 09:45:10 +0200 [thread overview]
Message-ID: <9dfdd7ce-ad1c-4845-95ee-d8ac5b5802e7@nvidia.com> (raw)
In-Reply-To: <20260128161030.39870-1-kuba@kernel.org>
On 28/01/2026 18:10, Jakub Kicinski wrote:
> Gal reports that BPF redirect increments dev->stats.tx_errors
> on failure. This is not correct, most modern drivers completely
> ignore dev->stats so these drops will be invisible to the user.
> Core code should use the dedicated core stats which are folded
> into device stats in dev_get_stats().
>
> Reported-by: Gal Pressman <gal@nvidia.com>
> Link: https://lore.kernel.org/c5df3b60-246a-4030-9c9a-0a35cd1ca924@nvidia.com
> Fixes: b4ab31414970 ("bpf: Add redirect_neigh helper as redirect drop-in")
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Aha, this kinda makes my mlx5 fix redundant.
I'm debating whether I should send a revert?
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 616e0520a0bb..2c21735798a5 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -2289,12 +2289,12 @@ static int __bpf_redirect_neigh_v6(struct sk_buff *skb, struct net_device *dev,
>
> err = bpf_out_neigh_v6(net, skb, dev, nh);
> if (unlikely(net_xmit_eval(err)))
> - DEV_STATS_INC(dev, tx_errors);
> + dev_core_stats_tx_dropped_inc(dev);
The commit message didn't mention anything about changing tx_errors to
tx_dropped.
next prev parent reply other threads:[~2026-01-29 7:45 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-28 16:10 [PATCH net] net: don't touch dev->stats in BPF redirect paths Jakub Kicinski
2026-01-28 18:37 ` Martin KaFai Lau
2026-01-29 7:45 ` Gal Pressman [this message]
2026-01-29 23:54 ` Jakub Kicinski
2026-01-29 8:15 ` Daniel Borkmann
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