From: Menglong Dong imagedong@tencent.com
[ Upstream commit fe94800184f22d4778628f1321dce5acb7513d84 ]
All of the subflows of a msk will be orphaned in mptcp_close(), which means the subflows are in DEAD state. After then, DATA_FIN will be sent, and the other side will response with a DATA_ACK for this DATA_FIN.
However, if the other side still has pending data, the data that received on these subflows will not be passed to the msk, as they are DEAD and subflow_data_ready() will not be called in tcp_data_ready(). Therefore, these data can't be acked, and they will be retransmitted again and again, until timeout.
Fix this by setting ssk->sk_socket and ssk->sk_wq to 'NULL', instead of orphaning the subflows in __mptcp_close(), as Paolo suggested.
Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close") Reviewed-by: Biao Jiang benbjiang@tencent.com Reviewed-by: Mengen Sun mengensun@tencent.com Signed-off-by: Menglong Dong imagedong@tencent.com Reviewed-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/mptcp/protocol.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index b568f55998f3..42d5e0a7952a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2297,12 +2297,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, goto out; }
- /* if we are invoked by the msk cleanup code, the subflow is - * already orphaned - */ - if (ssk->sk_socket) - sock_orphan(ssk); - + sock_orphan(ssk); subflow->disposable = 1;
/* if ssk hit tcp_done(), tcp_cleanup_ulp() cleared the related ops @@ -2833,7 +2828,11 @@ bool __mptcp_close(struct sock *sk, long timeout) if (ssk == msk->first) subflow->fail_tout = 0;
- sock_orphan(ssk); + /* detach from the parent socket, but allow data_ready to + * push incoming data into the mptcp stack, to properly ack it + */ + ssk->sk_socket = NULL; + ssk->sk_wq = NULL; unlock_sock_fast(ssk, slow); } sock_orphan(sk);