Fix deadlock in handle_error!() when we have HTLCs to fail-back.
authorMatt Corallo <git@bluematt.me>
Mon, 13 Jan 2020 21:10:30 +0000 (16:10 -0500)
committerJeffrey Czyz <jkczyz@gmail.com>
Wed, 1 Apr 2020 23:27:22 +0000 (16:27 -0700)
This partially reverts 933ae3470309f21ef7537ffbcdc42070d60e1e74,
though note that 933ae3470309f21ef7537ffbcdc42070d60e1e74 fixed a
similar deadlock while introducing this one.

If we have HTLCs to fail backwards, handle_error!() will call
finish_force_close_channel() which will attempt to lock channel_state
while it is locked at the original caller. Instead, hold the lock for
shorter scopes such that it is not held upon entering handle_error!().

Co-authored-by: Matt Corallo <git@bluematt.me>
Co-authored-by: Jeffrey Czyz <jkczyz@gmail.com>
lightning/src/ln/channelmanager.rs

index cde40ee323241cde60b14a400ab537e21477daa4..e9dfe5a5680c60249d02954865141a8054e0cc96 100644 (file)
@@ -467,21 +467,41 @@ pub struct ChannelDetails {
 }
 
 macro_rules! handle_error {
-       ($self: ident, $internal: expr, $their_node_id: expr, $locked_channel_state: expr) => {
+       ($self: ident, $internal: expr, $their_node_id: expr) => {
                match $internal {
                        Ok(msg) => Ok(msg),
                        Err(MsgHandleErrInternal { err, shutdown_finish }) => {
+                               #[cfg(debug_assertions)]
+                               {
+                                       // In testing, ensure there are no deadlocks where the lock is already held upon
+                                       // entering the macro.
+                                       assert!($self.channel_state.try_lock().is_ok());
+                               }
+
+                               let mut msg_events = Vec::with_capacity(2);
+
                                if let Some((shutdown_res, update_option)) = shutdown_finish {
                                        $self.finish_force_close_channel(shutdown_res);
                                        if let Some(update) = update_option {
-                                               $locked_channel_state.pending_msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
+                                               msg_events.push(events::MessageSendEvent::BroadcastChannelUpdate {
                                                        msg: update
                                                });
                                        }
                                }
+
                                log_error!($self, "{}", err.err);
                                if let msgs::ErrorAction::IgnoreError = err.action {
-                               } else { $locked_channel_state.pending_msg_events.push(events::MessageSendEvent::HandleError { node_id: $their_node_id, action: err.action.clone() }); }
+                               } else {
+                                       msg_events.push(events::MessageSendEvent::HandleError {
+                                               node_id: $their_node_id,
+                                               action: err.action.clone()
+                                       });
+                               }
+
+                               if !msg_events.is_empty() {
+                                       $self.channel_state.lock().unwrap().pending_msg_events.append(&mut msg_events);
+                               }
+
                                // Return error in case higher-API need one
                                Err(err)
                        },
@@ -1191,9 +1211,8 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
 
                let _ = self.total_consistency_lock.read().unwrap();
 
-               let mut channel_lock = self.channel_state.lock().unwrap();
                let err: Result<(), _> = loop {
-
+                       let mut channel_lock = self.channel_state.lock().unwrap();
                        let id = match channel_lock.short_to_id.get(&route.hops.first().unwrap().short_channel_id) {
                                None => return Err(APIError::ChannelUnavailable{err: "No channel available with first hop!"}),
                                Some(id) => id.clone(),
@@ -1242,7 +1261,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                        return Ok(());
                };
 
-               match handle_error!(self, err, route.hops.first().unwrap().pubkey, channel_lock) {
+               match handle_error!(self, err, route.hops.first().unwrap().pubkey) {
                        Ok(_) => unreachable!(),
                        Err(e) => { Err(APIError::ChannelUnavailable { err: e.err }) }
                }
@@ -1261,8 +1280,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                let _ = self.total_consistency_lock.read().unwrap();
 
                let (mut chan, msg, chan_monitor) = {
-                       let mut channel_state = self.channel_state.lock().unwrap();
-                       let (res, chan) = match channel_state.by_id.remove(temporary_channel_id) {
+                       let (res, chan) = match self.channel_state.lock().unwrap().by_id.remove(temporary_channel_id) {
                                Some(mut chan) => {
                                        (chan.get_outbound_funding_created(funding_txo)
                                                .map_err(|e| if let ChannelError::Close(msg) = e {
@@ -1272,7 +1290,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                                },
                                None => return
                        };
-                       match handle_error!(self, res, chan.get_their_node_id(), channel_state) {
+                       match handle_error!(self, res, chan.get_their_node_id()) {
                                Ok(funding_msg) => {
                                        (chan, funding_msg.0, funding_msg.1)
                                },
@@ -1284,12 +1302,9 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                if let Err(e) = self.monitor.add_monitor(chan_monitor.get_funding_txo().unwrap(), chan_monitor) {
                        match e {
                                ChannelMonitorUpdateErr::PermanentFailure => {
-                                       {
-                                               let mut channel_state = self.channel_state.lock().unwrap();
-                                               match handle_error!(self, Err(MsgHandleErrInternal::from_finish_shutdown("ChannelMonitor storage failure", *temporary_channel_id, chan.force_shutdown(true), None)), chan.get_their_node_id(), channel_state) {
-                                                       Err(_) => { return; },
-                                                       Ok(()) => unreachable!(),
-                                               }
+                                       match handle_error!(self, Err(MsgHandleErrInternal::from_finish_shutdown("ChannelMonitor storage failure", *temporary_channel_id, chan.force_shutdown(true), None)), chan.get_their_node_id()) {
+                                               Err(_) => { return; },
+                                               Ok(()) => unreachable!(),
                                        }
                                },
                                ChannelMonitorUpdateErr::TemporaryFailure => {
@@ -1520,10 +1535,8 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                                                                                },
                                                                                ChannelError::CloseDelayBroadcast { .. } => { panic!("Wait is only generated on receipt of channel_reestablish, which is handled by try_chan_entry, we don't bother to support it here"); }
                                                                        };
-                                                                       match handle_error!(self, err, their_node_id, channel_state) {
-                                                                               Ok(_) => unreachable!(),
-                                                                               Err(_) => { continue; },
-                                                                       }
+                                                                       handle_errors.push((their_node_id, err));
+                                                                       continue;
                                                                }
                                                        };
                                                        if let Err(e) = self.monitor.update_monitor(chan.get().get_funding_txo().unwrap(), monitor_update) {
@@ -1579,11 +1592,8 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                        };
                }
 
-               if handle_errors.len() > 0 {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       for (their_node_id, err) in handle_errors.drain(..) {
-                               let _ = handle_error!(self, err, their_node_id, channel_state_lock);
-                       }
+               for (their_node_id, err) in handle_errors.drain(..) {
+                       let _ = handle_error!(self, err, their_node_id);
                }
 
                if new_events.is_empty() { return }
@@ -1835,7 +1845,8 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                        return;
                };
 
-               let _ = handle_error!(self, err, their_node_id, channel_state_lock);
+               mem::drop(channel_state_lock);
+               let _ = handle_error!(self, err, their_node_id);
        }
 
        /// Gets the node_id held by this ChannelManager
@@ -2579,9 +2590,9 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
        #[doc(hidden)]
        pub fn update_fee(&self, channel_id: [u8;32], feerate_per_kw: u64) -> Result<(), APIError> {
                let _ = self.total_consistency_lock.read().unwrap();
-               let mut channel_state_lock = self.channel_state.lock().unwrap();
                let their_node_id;
                let err: Result<(), _> = loop {
+                       let mut channel_state_lock = self.channel_state.lock().unwrap();
                        let channel_state = &mut *channel_state_lock;
 
                        match channel_state.by_id.entry(channel_id) {
@@ -2620,7 +2631,7 @@ impl<ChanSigner: ChannelKeys, M: Deref, T: Deref, K: Deref, F: Deref> ChannelMan
                        return Ok(())
                };
 
-               match handle_error!(self, err, their_node_id, channel_state_lock) {
+               match handle_error!(self, err, their_node_id) {
                        Ok(_) => unreachable!(),
                        Err(e) => { Err(APIError::APIMisuseError { err: e.err })}
                }
@@ -2830,146 +2841,82 @@ impl<ChanSigner: ChannelKeys, M: Deref + Sync + Send, T: Deref + Sync + Send, K:
 {
        fn handle_open_channel(&self, their_node_id: &PublicKey, their_features: InitFeatures, msg: &msgs::OpenChannel) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_open_channel(their_node_id, their_features, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_open_channel(their_node_id, their_features, msg), *their_node_id);
        }
 
        fn handle_accept_channel(&self, their_node_id: &PublicKey, their_features: InitFeatures, msg: &msgs::AcceptChannel) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_accept_channel(their_node_id, their_features, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_accept_channel(their_node_id, their_features, msg), *their_node_id);
        }
 
        fn handle_funding_created(&self, their_node_id: &PublicKey, msg: &msgs::FundingCreated) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_funding_created(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_funding_created(their_node_id, msg), *their_node_id);
        }
 
        fn handle_funding_signed(&self, their_node_id: &PublicKey, msg: &msgs::FundingSigned) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_funding_signed(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_funding_signed(their_node_id, msg), *their_node_id);
        }
 
        fn handle_funding_locked(&self, their_node_id: &PublicKey, msg: &msgs::FundingLocked) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_funding_locked(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_funding_locked(their_node_id, msg), *their_node_id);
        }
 
        fn handle_shutdown(&self, their_node_id: &PublicKey, msg: &msgs::Shutdown) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_shutdown(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_shutdown(their_node_id, msg), *their_node_id);
        }
 
        fn handle_closing_signed(&self, their_node_id: &PublicKey, msg: &msgs::ClosingSigned) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_closing_signed(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_closing_signed(their_node_id, msg), *their_node_id);
        }
 
        fn handle_update_add_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateAddHTLC) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_update_add_htlc(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_update_add_htlc(their_node_id, msg), *their_node_id);
        }
 
        fn handle_update_fulfill_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFulfillHTLC) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_update_fulfill_htlc(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_update_fulfill_htlc(their_node_id, msg), *their_node_id);
        }
 
        fn handle_update_fail_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFailHTLC) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_update_fail_htlc(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_update_fail_htlc(their_node_id, msg), *their_node_id);
        }
 
        fn handle_update_fail_malformed_htlc(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFailMalformedHTLC) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_update_fail_malformed_htlc(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_update_fail_malformed_htlc(their_node_id, msg), *their_node_id);
        }
 
        fn handle_commitment_signed(&self, their_node_id: &PublicKey, msg: &msgs::CommitmentSigned) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_commitment_signed(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_commitment_signed(their_node_id, msg), *their_node_id);
        }
 
        fn handle_revoke_and_ack(&self, their_node_id: &PublicKey, msg: &msgs::RevokeAndACK) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_revoke_and_ack(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_revoke_and_ack(their_node_id, msg), *their_node_id);
        }
 
        fn handle_update_fee(&self, their_node_id: &PublicKey, msg: &msgs::UpdateFee) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_update_fee(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_update_fee(their_node_id, msg), *their_node_id);
        }
 
        fn handle_announcement_signatures(&self, their_node_id: &PublicKey, msg: &msgs::AnnouncementSignatures) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_announcement_signatures(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_announcement_signatures(their_node_id, msg), *their_node_id);
        }
 
        fn handle_channel_reestablish(&self, their_node_id: &PublicKey, msg: &msgs::ChannelReestablish) {
                let _ = self.total_consistency_lock.read().unwrap();
-               let res = self.internal_channel_reestablish(their_node_id, msg);
-               if res.is_err() {
-                       let mut channel_state_lock = self.channel_state.lock().unwrap();
-                       let _ = handle_error!(self, res, *their_node_id, channel_state_lock);
-               }
+               let _ = handle_error!(self, self.internal_channel_reestablish(their_node_id, msg), *their_node_id);
        }
 
        fn peer_disconnected(&self, their_node_id: &PublicKey, no_connection_possible: bool) {