6.16-stable review patch. If anyone has any objections, please let me know.
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From: Matthieu Baerts (NGI0) matttbe@kernel.org
commit 8708c5d8b3fb3f6d5d3b9e6bfe01a505819f519a upstream.
The disconnect test-case, with 'plain' TCP sockets generates spurious errors, e.g.
07 ns1 TCP -> ns1 (dead:beef:1::1:10006) MPTCP read: Connection reset by peer read: Connection reset by peer (duration 155ms) [FAIL] client exit code 3, server 3
netns ns1-FloSdv (listener) socket stat for 10006: TcpActiveOpens 2 0.0 TcpPassiveOpens 2 0.0 TcpEstabResets 2 0.0 TcpInSegs 274 0.0 TcpOutSegs 276 0.0 TcpOutRsts 3 0.0 TcpExtPruneCalled 2 0.0 TcpExtRcvPruned 1 0.0 TcpExtTCPPureAcks 104 0.0 TcpExtTCPRcvCollapsed 2 0.0 TcpExtTCPBacklogCoalesce 42 0.0 TcpExtTCPRcvCoalesce 43 0.0 TcpExtTCPChallengeACK 1 0.0 TcpExtTCPFromZeroWindowAdv 42 0.0 TcpExtTCPToZeroWindowAdv 41 0.0 TcpExtTCPWantZeroWindowAdv 13 0.0 TcpExtTCPOrigDataSent 164 0.0 TcpExtTCPDelivered 165 0.0 TcpExtTCPRcvQDrop 1 0.0
In the failing scenarios (TCP -> MPTCP), the involved sockets are actually plain TCP ones, as fallbacks for passive sockets at 2WHS time cause the MPTCP listeners to actually create 'plain' TCP sockets.
Similar to commit 218cc166321f ("selftests: mptcp: avoid spurious errors on disconnect"), the root cause is in the user-space bits: the test program tries to disconnect as soon as all the pending data has been spooled, generating an RST. If such option reaches the peer before the connection has reached the closed status, the TCP socket will report an error to the user-space, as per protocol specification, causing the above failure. Note that it looks like this issue got more visible since the "tcp: receiver changes" series from commit 06baf9bfa6ca ("Merge branch 'tcp-receiver-changes'").
Address the issue by explicitly waiting for the TCP sockets (-t) to reach a closed status before performing the disconnect. More precisely, the test program now waits for plain TCP sockets or TCP subflows in addition to the MPTCP sockets that were already monitored.
While at it, use 'ss' with '-n' to avoid resolving service names, which is not needed here.
Fixes: 218cc166321f ("selftests: mptcp: avoid spurious errors on disconnect") Cc: stable@vger.kernel.org Suggested-by: Paolo Abeni pabeni@redhat.com Reviewed-by: Mat Martineau martineau@kernel.org Reviewed-by: Geliang Tang geliang@kernel.org Signed-off-by: Matthieu Baerts (NGI0) matttbe@kernel.org Link: https://patch.msgid.link/20250912-net-mptcp-fix-sft-connect-v1-3-d40e77cbbf0... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/net/mptcp/mptcp_connect.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/tools/testing/selftests/net/mptcp/mptcp_connect.c +++ b/tools/testing/selftests/net/mptcp/mptcp_connect.c @@ -1248,7 +1248,7 @@ void xdisconnect(int fd) else xerror("bad family");
- strcpy(cmd, "ss -M | grep -q "); + strcpy(cmd, "ss -Mnt | grep -q "); cmdlen = strlen(cmd); if (!inet_ntop(addr.ss_family, raw_addr, &cmd[cmdlen], sizeof(cmd) - cmdlen)) @@ -1258,7 +1258,7 @@ void xdisconnect(int fd)
/* * wait until the pending data is completely flushed and all - * the MPTCP sockets reached the closed status. + * the sockets reached the closed status. * disconnect will bypass/ignore/drop any pending data. */ for (i = 0; ; i += msec_sleep) {