From: Jakub Kicinski <kuba@kernel.org>
To: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
Cc: Qihang <q.h.hack.winter@gmail.com>,
netdev@vger.kernel.org, daniel.zahka@gmail.com,
davem@davemloft.net, edumazet@google.com, pabeni@redhat.com,
horms@kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH net v5 2/2] packet: use consistent hard_header_len in TX_RING send path
Date: Mon, 3 Aug 2026 19:22:28 -0700 [thread overview]
Message-ID: <20260803192228.49a49867@kernel.org> (raw)
In-Reply-To: <willemdebruijn.kernel.f39af6152c60@gmail.com>
On Thu, 30 Jul 2026 05:22:21 -0400 Willem de Bruijn wrote:
> Qihang wrote:
> > tpacket_snd() reads dev->hard_header_len independently for skb
> > allocation and header construction in tpacket_fill_skb(). Concurrent
> > netdevice reconfiguration can therefore make the reserved headroom
> > smaller than the amount later pushed, or make copylen - hard_header_len
> > negative.
> >
> > Snapshot hard_header_len once before processing ring frames and use it
> > for the frame limit, headroom allocation, copy length, and skb
> > construction. Pass the snapshot to tpacket_fill_skb().
> >
> > The separate SOCK_DGRAM consistency problem between hard_header_len and
> > header_ops->create is not addressed here.
> >
> > Fixes: 69e3c75f4d54 ("net: TX_RING and packet mmap")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Qihang <q.h.hack.winter@gmail.com>
>
> Reviewed-by: Willem de Bruijn <willemb@google.com>
Willem, does the *shiko feedback look like false positives?
Both instances seem to provide different feedback, if I'm reading my own
tea leaves right Claude discarded the Gemini feedback about a panic
as a hallucination..
https://sashiko.dev/#/patchset/20260730082925.93759-2-q.h.hack.winter@gmail.com
https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260730082925.93759-2-q.h.hack.winter@gmail.com
next prev parent reply other threads:[~2026-08-04 2:22 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-30 8:29 [PATCH net v5 0/2] packet: use consistent hard_header_len in send paths Qihang
2026-07-30 8:29 ` [PATCH net v5 1/2] packet: use consistent hard_header_len in non-ring " Qihang
2026-07-30 8:29 ` [PATCH net v5 2/2] packet: use consistent hard_header_len in TX_RING send path Qihang
2026-07-30 9:22 ` Willem de Bruijn
2026-08-04 2:22 ` Jakub Kicinski [this message]
2026-08-04 3:04 ` Willem de Bruijn
2026-08-04 23:43 ` Jakub Kicinski
2026-08-05 13:35 ` Willem de Bruijn
2026-08-04 9:00 ` [PATCH net v6 0/3] net: fix hard_header_len races in packet send paths Qihang
2026-08-04 9:00 ` [PATCH net v6 1/3] net: remove CAP_SYS_RAWIO zero-padding in dev_validate_header Qihang
2026-08-04 12:16 ` Willem de Bruijn
2026-08-04 23:44 ` Jakub Kicinski
2026-08-04 9:32 ` [PATCH net v6 2/3] packet: use consistent hard_header_len in non-ring send paths Qihang
2026-08-04 9:33 ` [PATCH net v6 3/3] packet: use consistent hard_header_len in TX_RING send path Qihang
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