From 2929c8f7a20b3d8d910cebaf5c3bebaab13af5db Mon Sep 17 00:00:00 2001
From: steviez <steven@solana.com>
Date: Mon, 10 Oct 2022 15:37:23 -0400
Subject: [PATCH] Fix blockstore_processor::load_frozen_forks() halt_at_slot
 behavior (#28317)

load_frozen_forks() finds new slots to process by creating new Banks for
the children of the current slot in process_next_slots(). Prior to this
change, we would then immediately check if we had reached the
halt_at_slot and correctly halt processing when appropriate. As such, it
would be possible for Banks to be created for slots beyond the
halt_at_slot.

While a potential child slot that is past halt_at_slot wouldn't be
replayed, the Bank being created still alters some universal state in
AccountsDb. So, this change moves the halt_at_slot check before we
create children Banks in process_next_slots().
---
 ledger/src/blockstore_processor.rs | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/ledger/src/blockstore_processor.rs b/ledger/src/blockstore_processor.rs
index b57dc3b9d..fc3ae1d52 100644
--- a/ledger/src/blockstore_processor.rs
+++ b/ledger/src/blockstore_processor.rs
@@ -1440,9 +1440,8 @@ fn load_frozen_forks(
         &mut pending_slots,
     )?;
 
-    let halt_at_slot = opts.halt_at_slot.unwrap_or(std::u64::MAX);
     let on_halt_store_hash_raw_data_for_debug = opts.on_halt_store_hash_raw_data_for_debug;
-    if bank_forks.read().unwrap().root() != halt_at_slot {
+    if Some(bank_forks.read().unwrap().root()) != opts.halt_at_slot {
         let mut set_root_us = 0;
         let mut root_retain_us = 0;
         let mut process_single_slot_us = 0;
@@ -1588,6 +1587,17 @@ fn load_frozen_forks(
                 slot,
             );
 
+            let done_processing = opts
+                .halt_at_slot
+                .map(|halt_at_slot| slot >= halt_at_slot)
+                .unwrap_or(false);
+            if done_processing {
+                if opts.run_final_accounts_hash_calc {
+                    run_final_hash_calc(&bank, on_halt_store_hash_raw_data_for_debug);
+                }
+                break;
+            }
+
             process_next_slots(
                 &bank,
                 &meta,
@@ -1595,13 +1605,6 @@ fn load_frozen_forks(
                 leader_schedule_cache,
                 &mut pending_slots,
             )?;
-
-            if slot >= halt_at_slot {
-                if opts.run_final_accounts_hash_calc {
-                    run_final_hash_calc(&bank, on_halt_store_hash_raw_data_for_debug);
-                }
-                break;
-            }
         }
     } else if on_halt_store_hash_raw_data_for_debug {
         run_final_hash_calc(