diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2023-06-20 18:24:18 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-06-21 22:44:54 -0700 |
| commit | c2b2ae3925b65070adb27d5a31a31c376f26dec7 (patch) | |
| tree | f7fc3d3bda23abaea001e2c062001da2496d1b13 | |
| parent | 59bb14bda2f86550d10e65c9091ba442a0ac4b45 (diff) | |
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: 7d803344fdc3 ("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>
| -rw-r--r-- | net/mptcp/protocol.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 67311e7d5b21..86f8a7621aff 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1727,7 +1727,13 @@ static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, if (ret && ret != -EINPROGRESS && ret != -ERESTARTSYS && ret != -EINTR) *copied_syn = 0; } else if (ret && ret != -EINPROGRESS) { - mptcp_disconnect(sk, 0); + /* The disconnect() op called by tcp_sendmsg_fastopen()/ + * __inet_stream_connect() can fail, due to looking check, + * see mptcp_disconnect(). + * Attempt it again outside the problematic scope. + */ + if (!mptcp_disconnect(sk, 0)) + sk->sk_socket->state = SS_UNCONNECTED; } inet_sk(sk)->defer_connect = 0; @@ -2389,7 +2395,10 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk); if (!dispose_it) { - tcp_disconnect(ssk, 0); + /* The MPTCP code never wait on the subflow sockets, TCP-level + * disconnect should never fail + */ + WARN_ON_ONCE(tcp_disconnect(ssk, 0)); msk->subflow->state = SS_UNCONNECTED; mptcp_subflow_ctx_reset(subflow); release_sock(ssk); @@ -2812,7 +2821,7 @@ void mptcp_subflow_shutdown(struct sock *sk, struct sock *ssk, int how) break; fallthrough; case TCP_SYN_SENT: - tcp_disconnect(ssk, O_NONBLOCK); + WARN_ON_ONCE(tcp_disconnect(ssk, O_NONBLOCK)); break; default: if (__mptcp_check_fallback(mptcp_sk(sk))) { @@ -3075,11 +3084,10 @@ static int mptcp_disconnect(struct sock *sk, int flags) /* We are on the fastopen error path. We can't call straight into the * subflows cleanup code due to lock nesting (we are already under - * msk->firstsocket lock). Do nothing and leave the cleanup to the - * caller. + * msk->firstsocket lock). */ if (msk->fastopening) - return 0; + return -EBUSY; mptcp_listen_inuse_dec(sk); inet_sk_state_store(sk, TCP_CLOSE); |