From f6969dbc46da0baf42ce169c47c362d24e7cbcc9 Mon Sep 17 00:00:00 2001
From: Manav Darji <manavdarji.india@gmail.com>
Date: Mon, 15 Apr 2024 10:38:09 +0530
Subject: [PATCH] eth: close engine before handler for graceful shutdown
 (#1189)

---
 eth/backend.go | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/eth/backend.go b/eth/backend.go
index 3d18c71ac3..a7776df447 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -822,6 +822,12 @@ func (s *Ethereum) Stop() error {
 	// Stop all the peer-related stuff first.
 	s.ethDialCandidates.Close()
 	s.snapDialCandidates.Close()
+
+	// Close the engine before handler else it may cause a deadlock where
+	// the heimdall is unresponsive and the syncing loop keeps waiting
+	// for a response and is unable to proceed to exit `Finalize` during
+	// block processing.
+	s.engine.Close()
 	s.handler.Stop()
 
 	// Then stop everything else.
@@ -834,7 +840,6 @@ func (s *Ethereum) Stop() error {
 	s.txPool.Close()
 	s.miner.Close()
 	s.blockchain.Stop()
-	s.engine.Close()
 
 	// Clean shutdown marker as the last thing before closing db
 	s.shutdownTracker.Stop()