mptcp: avoid duplicated SUB_CLOSED events

commit d82809b 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: b911c97 ("mptcp: add netlink event support") Cc: [email protected] Tested-by: Arınç ÜNAL <[email protected]> Reviewed-by: Mat Martineau <[email protected]> Signed-off-by: Matthieu Baerts (NGI0) <[email protected]> Signed-off-by: Paolo Abeni <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
xanmod · Sep 4, 2024 · e38f07c · e38f07c
1 parent 119806a
commit e38f07c
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Showing 2 changed files with 8 additions and 1 deletion.
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
@@ -2508,6 +2508,12 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
 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
@@ -519,7 +519,8 @@ 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;
 	bool	data_avail;
 	bool	scheduled;
 	u32	remote_nonce;