From 4abd18f6cda8fe3cc46ddee7ccc84d5fd5068cfa Mon Sep 17 00:00:00 2001
From: "mergify[bot]" <37929162+mergify[bot]@users.noreply.github.com>
Date: Thu, 30 Nov 2023 17:58:40 -0500
Subject: [PATCH] v1.17: Skip shrink until startup verification is complete
 (backport of #34209) (#34227)

---
 runtime/src/accounts_background_service.rs | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/runtime/src/accounts_background_service.rs b/runtime/src/accounts_background_service.rs
index b826f8eddc5724..09f3758ab34a21 100644
--- a/runtime/src/accounts_background_service.rs
+++ b/runtime/src/accounts_background_service.rs
@@ -708,9 +708,21 @@ impl AccountsBackgroundService {
                             bank.force_flush_accounts_cache();
                             bank.clean_accounts(last_full_snapshot_slot);
                             last_cleaned_block_height = bank.block_height();
-                            bank.shrink_ancient_slots();
+                            // See justification below for why we skip 'shrink' here.
+                            if bank.is_startup_verification_complete() {
+                                bank.shrink_ancient_slots();
+                            }
+                        }
+                        // Do not 'shrink' until *after* the startup verification is complete.
+                        // This is because startup verification needs to get the snapshot
+                        // storages *as they existed at startup* (to calculate the accounts hash).
+                        // If 'shrink' were to run, then it is possible startup verification
+                        // (1) could race with 'shrink', and fail to assert that shrinking is not in
+                        // progress, or (2) could get snapshot storages that were newer than what
+                        // was in the snapshot itself.
+                        if bank.is_startup_verification_complete() {
+                            bank.shrink_candidate_slots();
                         }
-                        bank.shrink_candidate_slots();
                     }
                     stats.record_and_maybe_submit(start_time.elapsed());
                     sleep(Duration::from_millis(INTERVAL_MS));