Re: [PATCH bpf 1/2] bpf: Fix bpf_skb_change_tail wrt csum partial skbs

[patchwork-bot+netdevbpf@kernel.org]

Hello:

This series was applied to bpf/bpf.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Mon,  7 Sep 2026 14:10:24 +0200 you wrote:
> Cilium generates ICMP "frag needed" replies from BPF when a LB DSR
> packet exceeds the egress MTU. The reply is built by first trimming the
> packet down to target size via bpf_skb_change_tail(), and then pushing
> the ICMP error headers in front of it.
> 
> The trim is rejected for skbs which carry a checksum offload, e.g. TCP
> packets aggregated by GRO on ingress where tcp_gro_complete() leaves
> the skb as CHECKSUM_PARTIAL. __bpf_skb_min_len() raises the minimum
> length to the end of the L4 checksum field, so a trim to 42 bytes bails
> out with -EINVAL given a min_len of 52 in this case, and due to that
> the ICMP generator fails. This is not the case if GRO is turned off.
> 
> [...]

Here is the summary with links:
  - [bpf,1/2] bpf: Fix bpf_skb_change_tail wrt csum partial skbs
    https://git.kernel.org/bpf/bpf/c/3b55f350c68a
  - [bpf,2/2] selftests/bpf: Add test for bpf_skb_change_tail on csum partial skbs
    https://git.kernel.org/bpf/bpf/c/15e2565f1c43

You are awesome, thank you!
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