From: Gang Yan <yangang@kylinos.cn>

Changelog:
v4:
  - Update the coomit log to show the root cause.
  - Remove the '__mptcp_propagate_sndbuf' in 'mptcp_sk_clone_init'
    according to Paolo's advice.
  - Replace 'grep' with 'sed' according to AI's suggestions.
  - Crete a packetdrill PR for test:
    https://github.com/multipath-tcp/packetdrill/pull/193
v3:
  - Add a check in diag.sh to check the sndbuf of the server side.

Gang Yan (2):
  mptcp: sync the msk->sndbuf at accept() time
  selftests: mptcp: add a check for sndbuf of S/C

 net/mptcp/protocol.c                      |  2 +-
 tools/testing/selftests/net/mptcp/diag.sh | 28 +++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

-- 
2.43.0

Hi Gang,

On 11/04/2026 05:48, Gang Yan wrote:
> From: Gang Yan <yangang@kylinos.cn>
> 
> Changelog:
> v4:
>   - Update the coomit log to show the root cause.
>   - Remove the '__mptcp_propagate_sndbuf' in 'mptcp_sk_clone_init'
>     according to Paolo's advice.
>   - Replace 'grep' with 'sed' according to AI's suggestions.
>   - Crete a packetdrill PR for test:
>     https://github.com/multipath-tcp/packetdrill/pull/193

Thank you for these patches. Now in our tree:

New patches for t/upstream-net and t/upstream:
- 3fb2d76a499a: mptcp: sync the msk->sndbuf at accept() time
- a30244625bec: selftests: mptcp: add a check for sndbuf of S/C
- Results: 04a2a52011ad..46cef22df2cd (export-net)
- Results: f4ace5138b04..bbaa3169f0ab (export)

Tests are now in progress:

- export-net:
https://github.com/multipath-tcp/mptcp_net-next/commit/c654c5c9b558ff5c29ceb069e91a2a23f9aadce4/checks
- export:
https://github.com/multipath-tcp/mptcp_net-next/commit/b587e221edde5e92c4aed7fd8c58f258ee164de1/checks

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Hi Gang,

On 11/04/2026 05:48, Gang Yan wrote:
> From: Gang Yan <yangang@kylinos.cn>
> 
> Changelog:
> v4:
>   - Update the coomit log to show the root cause.
>   - Remove the '__mptcp_propagate_sndbuf' in 'mptcp_sk_clone_init'
>     according to Paolo's advice.
>   - Replace 'grep' with 'sed' according to AI's suggestions.
>   - Crete a packetdrill PR for test:
>     https://github.com/multipath-tcp/packetdrill/pull/193

Thank you for the new version and the new packetdrill test. It looks
good to me.

Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

Hi Gang,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal (except selftest_mptcp_join): Unstable: 1 failed test(s): packetdrill_mp_reset ⚠️ 
- KVM Validation: normal (only selftest_mptcp_join): Success! ✅
- KVM Validation: debug (except selftest_mptcp_join): Success! ✅
- KVM Validation: debug (only selftest_mptcp_join): Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/24274365063

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/414e68b0e64e
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1080031


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)