The '-f' parameter is there to force the kernel to emit MPTCP FASTCLOSE by closing the connection with unread bytes in the receive queue.

The xdisconnect() helper was used to stop the connection, but it does more than that: it will shut it down, then wait before reconnecting to the same address. This causes the mptcp_join's "fastclose test" to fail all the time.

This failure is due to a recent change, with commit 218cc166321f ("selftests: mptcp: avoid spurious errors on disconnect"), but that went unnoticed because the test is currently ignored. The recent modification only shown an existing issue: xdisconnect() doesn't need to be used here, only the shutdown() part is needed.

Fixes: 6bf41020b72b ("selftests: mptcp: update and extend fastclose test-cases") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau martineau@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org --- Notes: - The failure was not clearly visible on NIPA, because the results for the two impacted sub-tests are currently ignored (unstable). Still, it looks important to fix that, as this will help when the tests will be improved not to be unstable any more. --- tools/testing/selftests/net/mptcp/mptcp_connect.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.c b/tools/testing/selftests/net/mptcp/mptcp_connect.c index 414addef9a4514c489ecd09249143fe0ce2af649..d240d02fa443a1cd802f0e705ab36db5c22063a8 100644 --- a/tools/testing/selftests/net/mptcp/mptcp_connect.c +++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c @@ -1302,7 +1302,7 @@ int main_loop(void) return ret;

if (cfg_truncate > 0) { - xdisconnect(fd); + shutdown(fd, SHUT_WR); } else if (--cfg_repeat > 0) { xdisconnect(fd);

--- base-commit: 4241a702e0d0c2ca9364cfac08dbf134264962de change-id: 20250204-net-mptcp-sft-conn-f-d1c14274ba66

Best regards,