From: Gang Yan <yangang@kylinos.cn>


Hi Matt, Paolo:

During my testing, I discovered two issues in MPTCP related to the 
backlog_list, both of which can lead to transmission stalls. In this
patchset, I have added a test program to reproduce the issues, along with
two workarounds. Additional details and more specific workarounds are also
included in the notes to help clarify the exact scenarios where the
problems occur.

I would appreciate your feedback and hope we can find a better fix for
these issues.

Gang Yan (3):
  mptcp: add backlog_list bug reproducer test
  mptcp: fix receive stalls when 'ack_seq' in backlog_list
  mptcp: fix stall because of data_ready

 net/mptcp/protocol.c                          |   9 +-
 tools/testing/selftests/net/mptcp/Makefile    |   1 +
 .../testing/selftests/net/mptcp/multi_chunk.c | 148 ++++++++++++++++++
 .../selftests/net/mptcp/multi_chunk.sh        |  37 +++++
 4 files changed, 192 insertions(+), 3 deletions(-)
 create mode 100644 tools/testing/selftests/net/mptcp/multi_chunk.c
 create mode 100755 tools/testing/selftests/net/mptcp/multi_chunk.sh

-- 
2.43.0

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): Success! ✅
- 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/21701956586

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/189e81c8d4e0
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1051012


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)