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| author | Paolo Abeni <pabeni@redhat.com> | 2023-06-20 19:24:18 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-06-28 12:12:24 +0300 |
| commit | b7bb71dfb541df376c21c24451369fea83c4f327 (patch) | |
| tree | 394c3b900aa1075fe382687288a5585a701d3f25 | |
| parent | 1d9dc9bed9996f35bd7b1ceec690e617f760bc58 (diff) | |
| download | linux-b7bb71dfb541df376c21c24451369fea83c4f327.tar.xz | |
mptcp: handle correctly disconnect() failures
commit c2b2ae3925b65070adb27d5a31a31c376f26dec7 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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 59186997c3e2..fffcbc881c98 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1708,7 +1708,13 @@ static int mptcp_sendmsg_fastopen(struct sock *sk, struct sock *ssk, struct msgh 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; } return ret; @@ -2375,7 +2381,10 @@ 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); @@ -2799,7 +2808,7 @@ 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))) { @@ -3053,11 +3062,10 @@ 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; inet_sk_state_store(sk, TCP_CLOSE); |