From 441fed7a5bc0ebb3ef16eece71d08794a41b1620 Mon Sep 17 00:00:00 2001
From: Rob Walker <rob@solana.com>
Date: Tue, 28 May 2019 12:25:55 -0700
Subject: [PATCH] check freeze before updating slot_hashes (#4448)

* check freeze before updating slot_hashes

* fixup
---
 runtime/src/bank.rs | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/runtime/src/bank.rs b/runtime/src/bank.rs
index 0f1a963f5d..9021555063 100644
--- a/runtime/src/bank.rs
+++ b/runtime/src/bank.rs
@@ -215,18 +215,22 @@ impl Bank {
         self.store(&slot_hashes::id(), &account);
     }
 
-    fn set_hash(&self) {
+    fn set_hash(&self) -> bool {
         let mut hash = self.hash.write().unwrap();
 
         if *hash == Hash::default() {
             //  freeze is a one-way trip, idempotent
             *hash = self.hash_internal_state();
+            true
+        } else {
+            false
         }
     }
 
     pub fn freeze(&self) {
-        self.set_hash();
-        self.update_slot_hashes();
+        if self.set_hash() {
+            self.update_slot_hashes();
+        }
     }
 
     pub fn epoch_schedule(&self) -> &EpochSchedule {