linux-kernel - [PATCH net] selftests: mptcp: connect: -f: no reconnect

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Message-Id: <20250204-net-mptcp-sft-conn-f-v1-1-6b470c72fffa@kernel.org>
Date: Tue, 04 Feb 2025 23:19:53 +0100
From: "Matthieu Baerts (NGI0)" <matttbe@...nel.org>
To: mptcp@...ts.linux.dev, Mat Martineau <martineau@...nel.org>, 
 Geliang Tang <geliang@...nel.org>, "David S. Miller" <davem@...emloft.net>, 
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
 Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, 
 Shuah Khan <shuah@...nel.org>
Cc: netdev@...r.kernel.org, linux-kselftest@...r.kernel.org, 
 linux-kernel@...r.kernel.org, stable@...r.kernel.org, 
 "Matthieu Baerts (NGI0)" <matttbe@...nel.org>
Subject: [PATCH net] selftests: mptcp: connect: -f: no reconnect

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@...r.kernel.org
Reviewed-by: Mat Martineau <martineau@...nel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@...nel.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,
-- 
Matthieu Baerts (NGI0) <matttbe@...nel.org>