[PATCH net v2 0/2] net: gro: fix frag0 and remcsum handling

[Eric Dumazet <edumazet@kernel.org>]

Two GRO fixes for paths using remote checksum offload (VXLAN, GUE)
and for NAPI_GRO_CB(skb)->frag0 after a pull.

Patch 1 skips skb_gro_remcsum_cleanup() once the skb was merged,
as grc->offset can no longer be trusted.

Patch 2 invalidates frag0 before a pull, which commit bd56a29c7a4e
("net: gro: change skb_gro_network_header()") stopped doing.

v2:
- Patch 1: reword the comment and changelog: skb->data is not always
  moved (frag/head steal), and fraglist members keep their adjusted
  inner checksum, which is the intended value (Sashiko).
- Patch 2: invalidate frag0 before the pull, as __pskb_pull_tail()
  can fail after pskb_expand_head() freed the old head (Sashiko).
- Patch 2: add a Fixes: tag for UDP fraglist GRO, which pulls
  directly since before bd56a29c7a4e (Sashiko).
- CC Tom Herbert and stable.

v1: https://lore.kernel.org/netdev/20261028141325.2103814-1-edumazet@kernel.org/


Eric Dumazet (2):
  net: gro: do not undo remote checksum offload on merged packets
  net: gro: invalidate frag0 after a pull

 include/net/gro.h       | 18 +++++++++++++++++-
 net/core/gro.c          |  1 +
 net/ipv4/esp4_offload.c |  1 +
 net/ipv4/udp_offload.c  |  1 +
 net/ipv6/esp6_offload.c |  1 +
 5 files changed, 21 insertions(+), 1 deletion(-)

-- 
2.53.0