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mptcp: handle correctly disconnect() failures
Currently the mptcp code has assumes that disconnect() can fail only
at mptcp_sendmsg_fastopen() time - to avoid a deadlock scenario - and
don't even bother returning an error code.
Soon mptcp_disconnect() will handle more error conditions: let's track
them explicitly.
As a bonus, explicitly annotate TCP-level disconnect as not failing:
the mptcp code never blocks for event on the subflows.
Fixes: 7d803344fd
("mptcp: fix deadlock in fastopen error path")
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
parent
59bb14bda2
commit
c2b2ae3925
1 changed files with 14 additions and 6 deletions
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@ -1727,7 +1727,13 @@ static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
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if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR)
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*copied_syn = 0;
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} else if (ret && ret != -EINPROGRESS) {
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mptcp_disconnect(sk, 0);
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/* The disconnect() op called by tcp_sendmsg_fastopen()/
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* __inet_stream_connect() can fail, due to looking check,
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* see mptcp_disconnect().
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* Attempt it again outside the problematic scope.
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*/
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if (!mptcp_disconnect(sk, 0))
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sk->sk_socket->state = SS_UNCONNECTED;
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}
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inet_sk(sk)->defer_connect = 0;
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@ -2389,7 +2395,10 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk,
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need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);
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if (!dispose_it) {
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tcp_disconnect(ssk, 0);
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/* The MPTCP code never wait on the subflow sockets, TCP-level
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* disconnect should never fail
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*/
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WARN_ON_ONCE(tcp_disconnect(ssk, 0));
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msk->subflow->state = SS_UNCONNECTED;
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mptcp_subflow_ctx_reset(subflow);
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release_sock(ssk);
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@ -2812,7 +2821,7 @@ void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how)
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break;
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fallthrough;
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case TCP_SYN_SENT:
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tcp_disconnect(ssk, O_NONBLOCK);
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WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK));
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break;
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default:
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if (__mptcp_check_fallback(mptcp_sk(sk))) {
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@ -3075,11 +3084,10 @@ static int mptcp_disconnect(struct sock *sk, int flags)
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/* We are on the fastopen error path. We can't call straight into the
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* subflows cleanup code due to lock nesting (we are already under
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* msk->firstsocket lock). Do nothing and leave the cleanup to the
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* caller.
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* msk->firstsocket lock).
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*/
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if (msk->fastopening)
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return 0;
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return -EBUSY;
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mptcp_listen_inuse_dec(sk);
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inet_sk_state_store(sk, TCP_CLOSE);
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