Re: [PATCH mptcp-next v2 00/12] mptcp: receive path improvement

[Matthieu Baerts <matttbe@kernel.org>]

On 19/09/2025 10:14, Matthieu Baerts wrote:
> Hi Paolo,
> 
> On 19/09/2025 08:54, Paolo Abeni wrote:
>> On 9/19/25 4:22 AM, Geliang Tang wrote:
>>> On Thu, 2025-09-18 at 20:33 +0000, MPTCP CI wrote:
>>>> Hi Paolo,
>>>>
>>>> Thank you for your modifications, that's great!
>>>>
>>>> Our CI did some validations and here is its report:
>>>>
>>>> - KVM Validation: normal: Unstable: 5 failed test(s):
>>>> packetdrill_mp_capable selftest_mptcp_connect
>>>> selftest_mptcp_connect_checksum selftest_mptcp_connect_mmap
>>>> selftest_mptcp_connect_sendfile 🔴
>>>> - KVM Validation: debug: Unstable: 5 failed test(s):
>>>> packetdrill_mp_capable selftest_mptcp_connect
>>>> selftest_mptcp_connect_checksum selftest_mptcp_connect_mmap
>>>> selftest_mptcp_connect_sendfile 🔴
>>>> - 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/17836736262
>>>
>>> CI reports that this series breaks the mptcp_connect.sh test:
>>>
>>> # INFO: disconnect
>>> # 63 ns1 MPTCP -> ns1 (10.0.1.1:20001      ) MPTCP     (duration 
>>> 1348ms) [ OK ]
>>> # 64 ns1 MPTCP -> ns1 (10.0.1.1:20002      ) TCP       main_loop_s:
>>> timed out
>>> # (duration 61185ms) [FAIL] client exit code 124, server 2
>>> # 
>>> # netns ns1-HugJD9 (listener) socket stat for 20002:
>>> # Netid State     Recv-Q Send-Q Local Address:Port  Peer Address:Port 
>>> # tcp   TIME-WAIT 0      0           10.0.1.1:20002     10.0.1.1:47722
>>> timer:(timewait,,0) ino:0 sk:2066
>>> # ^I
>>> # TcpActiveOpens                  2                  0.0
>>> # TcpPassiveOpens                 2                  0.0
>>>
>>> I also tested it on my end and found that starting from patch 8 "mptcp:
>>> cleanup fallback data fin reception", the mptcp_connect.sh test has
>>> been failing.
>>>
>>> I apologize for not providing this feedback during the v1 review, but I
>>> was too busy yesterday to complete the testing.
>>
>> Thank you very much for bisecting. I did not observe the failures on v1,
>> but I see them on v2 (which is quite suprising, giving no big changes in
>> there). I submitted v2 anyway to give syzkaller/CI a chance to run more.
> 
> It looks like the CI had the same issues with the v1:
> 
> https://github.com/multipath-tcp/mptcp_net-next/actions/runs/17795536153

Note that these issues were probably not visible on your side when you
developed the v1, with an older base. For mptcp_connect*.sh, it looks
like they are failing in the 'disconnect' part, due to a recent
modification in the selftests:

https://lore.kernel.org/20250912-net-mptcp-fix-sft-connect-v1-3-d40e77cbbf02@kernel.org

Now the TCP connections are listed, and one stays open. The packetdrill
failure looks strange: a RST is sent in reply to a FIN+ACK.

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