From: Jesper Dangaard Brouer <hawk@kernel•org>
To: Maciej Fijalkowski <maciej.fijalkowski@intel•com>,
Jakub Kicinski <kuba@kernel•org>
Cc: bpf@vger•kernel.org, ast@kernel•org, daniel@iogearbox•net,
netdev@vger•kernel.org, magnus.karlsson@intel•com,
aleksander.lobakin@intel•com, ilias.apalodimas@linaro•org,
toke@redhat•com, lorenzo@kernel•org,
syzbot+ff145014d6b0ce64a173@syzkaller•appspotmail.com,
Ihor Solodrai <ihor.solodrai@linux•dev>,
Octavian Purdila <tavip@google•com>
Subject: Re: [PATCH v5 bpf 1/2] xdp: introduce xdp_convert_skb_to_buff()
Date: Wed, 5 Nov 2025 19:39:46 +0100 [thread overview]
Message-ID: <49edb9fa-56be-4853-aced-429f5b40b4be@kernel.org> (raw)
In-Reply-To: <aQidBn22H1UVxST5@boxer>
On 03/11/2025 13.16, Maciej Fijalkowski wrote:
> On Fri, Oct 31, 2025 at 11:49:52AM -0700, Jakub Kicinski wrote:
>> On Fri, 31 Oct 2025 12:37:37 +0100 Maciej Fijalkowski wrote:
>>>>> would be fine for you? Plus AI reviewer has kicked me in the nuts on veth
>>>>> patch so have to send v6 anyways.
>>>>
>>>> The veth side unfortunately needs more work than Mr Robot points out.
>>>> For some reason veth tries to turn skb into an xdp_frame..
>>>
>>> That is beyond the scope of the fix that I started doing as you're
>>> undermining overall XDP support in veth, IMHO.
>>>
>>> I can follow up on this on some undefined future but right now I will
>>> have to switch to some other work.
>>>
>>> If you disagree and insist on addressing skb->xdp_frame in veth within
>>> this patchset then I'm sorry but I will have to postpone my activities
>>> here.
>>
>> Yeah, I understand. A lot of the skb<>XDP integration is a steaming
>> pile IMO, as mentioned elsewhere. I'd like to keep the core clean
>> tho, so if there's some corner cases in veth after your changes
>> I'll live. But I'm worried that the bugs in veth will make you
>> want to preserve the conditional in xdp_convert_skb_to_buff() :(
>
> Probably the conditional would cover these corner cases, but I am not
> insisting on it. skb_pp_cow_data() is called under certain circumstances
> in veth but I have never seen a case on my side where it was skipped,
> mostly because of headroom size being too small.
This reminds me that we should change/increase veth
net_device.needed_headroom when there is an XDP prog attached.
As you said, today all SKB will basically get mem reallocated.
--Jesper
next prev parent reply other threads:[~2025-11-05 18:39 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-29 22:13 [PATCH v5 bpf 0/2] xdp: fix page_pool leaks Maciej Fijalkowski
2025-10-29 22:13 ` [PATCH v5 bpf 1/2] xdp: introduce xdp_convert_skb_to_buff() Maciej Fijalkowski
2025-10-29 23:50 ` Jakub Kicinski
2025-10-30 12:14 ` Maciej Fijalkowski
2025-10-30 15:25 ` Jakub Kicinski
2025-10-30 20:22 ` Maciej Fijalkowski
2025-10-31 2:05 ` Jakub Kicinski
2025-10-31 11:37 ` Maciej Fijalkowski
2025-10-31 18:49 ` Jakub Kicinski
2025-11-03 12:16 ` Maciej Fijalkowski
2025-11-05 18:39 ` Jesper Dangaard Brouer [this message]
2025-10-29 22:13 ` [PATCH v5 bpf 2/2] veth: update mem type in xdp_buff Maciej Fijalkowski
2025-10-29 22:59 ` bot+bpf-ci
2025-10-31 12:46 ` Maciej Fijalkowski
2025-10-31 13:45 ` Chris Mason
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