Re: [PATCH net v5 2/2] packet: use consistent hard_header_len in TX_RING send path
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-08-04 02:22:30
Also in:
stable
On Thu, 30 Jul 2026 05:22:21 -0400 Willem de Bruijn wrote:
Qihang wrote:quoted
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 <redacted>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