Re: [PATCH 1/4] net: hsr: fix packet drops caused by GRO superpackets
From: Jakub Kicinski <kuba@kernel.org>
Date: 2026-08-14 01:21:12
Also in:
linux-kselftest, lkml, stable
On Sun, 9 Aug 2026 14:14:51 +0200 Xin Xie wrote:
HSR/PRP process each wire frame separately for tagging and duplicate discard. GRO on a lower device hides multiple frames in one skb, which cannot be forwarded with valid per-frame metadata. Disable GRO and GRO_HW when a lower device is enslaved, matching the existing LRO handling. This is best effort because GRO may be re-enabled and some devices cannot disable GRO_HW. The forward-entry segmentation fix handles plain, trailer-free GSO skbs that still arrive; device-specific fixed-on GRO_HW output is outside this guarantee.
1) could you explain in more detail why GRO is breaking things? GRO shouldn't merge packets with different L2/L2.5 and packets with trailers? 2) the code seems inspired by LRO but LRO also has NETIF_F_UPPER_DISABLES. This change looks rather incomplete. Calling it "best effort" seems like an excuse. 3) Clashiko has a number of other comments: https://netdev-ai.bots.linux.dev/sashiko/#/patchset/20260809121455.1745-1-xiexinet@gmail.com -- pw-bot: cr