From ce36f2c20be59452aa3414692cb2b4a175047b10 Mon Sep 17 00:00:00 2001 From: Elias Rohrer Date: Wed, 17 Apr 2024 11:54:25 +0200 Subject: [PATCH] Acquire `per_peer_state` `write` lock earlier in `ChannelManager::write` Previously, we would hold the `per_peer_state` `read` lock during the serialization of channel objects. While this might have reduced lock congestion minimally, we also calculated the number of serializable peers in this phase, only to use it later after dropping and reacquiring the `per_peer_state` `write` lock. This could potentially result in inconsistiencies if the `serializable_peer_count` would change after we dropped the `read` lock but before we acquired the `write` lock. To mitigate the issue we just acquire the `write` lock ealier and hold it for the remainder of `ChannelManager::write`. --- lightning/src/ln/channelmanager.rs | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index abbab5ff0..6581500d7 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -11035,9 +11035,10 @@ where best_block.block_hash.write(writer)?; } + let per_peer_state = self.per_peer_state.write().unwrap(); + let mut serializable_peer_count: u64 = 0; { - let per_peer_state = self.per_peer_state.read().unwrap(); let mut number_of_funded_channels = 0; for (_, peer_state_mutex) in per_peer_state.iter() { let mut peer_state_lock = peer_state_mutex.lock().unwrap(); @@ -11084,8 +11085,6 @@ where decode_update_add_htlcs_opt = Some(decode_update_add_htlcs); } - let per_peer_state = self.per_peer_state.write().unwrap(); - let pending_inbound_payments = self.pending_inbound_payments.lock().unwrap(); let claimable_payments = self.claimable_payments.lock().unwrap(); let pending_outbound_payments = self.pending_outbound_payments.pending_outbound_payments.lock().unwrap(); -- 2.39.5