From a088190f3fbf304f45c80e25c44cc267293270ab Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Tue, 3 Sep 2024 12:17:48 +0200 Subject: [PATCH] mptcp: avoid duplicated SUB_CLOSED events MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit d82809b6c5f2676b382f77a5cbeb1a5d91ed2235 upstream. The initial subflow might have already been closed, but still in the connection list. When the worker is instructed to close the subflows that have been marked as closed, it might then try to close the initial subflow again. A consequence of that is that the SUB_CLOSED event can be seen twice: # ip mptcp endpoint 1.1.1.1 id 1 subflow dev eth0 2.2.2.2 id 2 subflow dev eth1 # ip mptcp monitor & [ CREATED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 [ ESTABLISHED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 [ SF_ESTABLISHED] remid=0 locid=2 saddr4=2.2.2.2 daddr4=9.9.9.9 # ip mptcp endpoint delete id 1 [ SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 [ SF_CLOSED] remid=0 locid=0 saddr4=1.1.1.1 daddr4=9.9.9.9 The first one is coming from mptcp_pm_nl_rm_subflow_received(), and the second one from __mptcp_close_subflow(). To avoid doing the post-closed processing twice, the subflow is now marked as closed the first time. Note that it is not enough to check if we are dealing with the first subflow and check its sk_state: the subflow might have been reset or closed before calling mptcp_close_ssk(). Fixes: b911c97c7dc7 ("mptcp: add netlink event support") Cc: stable@vger.kernel.org Tested-by: Arınç ÜNAL Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Paolo Abeni [ Conflict in protocol.h due to commit f1f26512a9bf ("mptcp: use plain bool instead of custom binary enum") and more that are not in this version, because they modify the context and the size of __unused. The conflict is easy to resolve, by not modifying data_avail type. ] Signed-off-by: Matthieu Baerts (NGI0) Signed-off-by: Greg Kroah-Hartman --- net/mptcp/protocol.c | 6 ++++++ net/mptcp/protocol.h | 3 ++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 0ae684624c82..5edc039179f3 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -2471,6 +2471,12 @@ out: void mptcp_close_ssk(struct sock *sk, struct sock *ssk, struct mptcp_subflow_context *subflow) { + /* The first subflow can already be closed and still in the list */ + if (subflow->close_event_done) + return; + + subflow->close_event_done = true; + if (sk->sk_state == TCP_ESTABLISHED) mptcp_event(MPTCP_EVENT_SUB_CLOSED, mptcp_sk(sk), ssk, GFP_KERNEL); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 940fd9400648..6ba857079a4d 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -500,7 +500,8 @@ struct mptcp_subflow_context { stale : 1, /* unable to snd/rcv data, do not use for xmit */ valid_csum_seen : 1, /* at least one csum validated */ is_mptfo : 1, /* subflow is doing TFO */ - __unused : 10; + close_event_done : 1, /* has done the post-closed part */ + __unused : 9; enum mptcp_data_avail data_avail; bool scheduled; u32 remote_nonce;