From fdc11f2c76617bc05d8b2c052186f233a34dc709 Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Fri, 7 May 2021 22:17:29 +0000 Subject: [PATCH] Do not wait in PersistenceNotifier when the persist flag is set When we had a event which caused us to set the persist flag in a PersistenceNotifier in between wait calls, we will still wait, potentially not persisting a ChannelManager when we should. Worse, for wait_timeout, this caused us to always wait up to the timeout, but then always return true that a persistence is needed. Instead, we simply check the persist flag before waiting, returning immediately if it is set. --- lightning/src/ln/channelmanager.rs | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs index 9efb6b83b..cf6e8cf3f 100644 --- a/lightning/src/ln/channelmanager.rs +++ b/lightning/src/ln/channelmanager.rs @@ -4088,6 +4088,10 @@ impl PersistenceNotifier { loop { let &(ref mtx, ref cvar) = &self.persistence_lock; let mut guard = mtx.lock().unwrap(); + if *guard { + *guard = false; + return; + } guard = cvar.wait(guard).unwrap(); let result = *guard; if result { @@ -4103,6 +4107,10 @@ impl PersistenceNotifier { loop { let &(ref mtx, ref cvar) = &self.persistence_lock; let mut guard = mtx.lock().unwrap(); + if *guard { + *guard = false; + return true; + } guard = cvar.wait_timeout(guard, max_wait).unwrap().0; // Due to spurious wakeups that can happen on `wait_timeout`, here we need to check if the // desired wait time has actually passed, and if not then restart the loop with a reduced wait -- 2.39.5