From c9e58743e75dcaae5e672a4ef02e00536daa73db Mon Sep 17 00:00:00 2001
From: Tyera Eulberg <teulberg@gmail.com>
Date: Thu, 26 Sep 2019 19:40:18 -0600
Subject: [PATCH] Prevent subtract overflow panic when slot <
 MAX_LOCKOUT_HISTORY (#6135)

---
 core/src/rpc.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/core/src/rpc.rs b/core/src/rpc.rs
index 8d85238676..a95ba47f7d 100644
--- a/core/src/rpc.rs
+++ b/core/src/rpc.rs
@@ -163,7 +163,11 @@ impl JsonRpcRequestProcessor {
                 }
             })
             .partition(|vote_account_info| {
-                vote_account_info.last_vote >= bank.slot() - MAX_LOCKOUT_HISTORY as u64
+                if bank.slot() >= MAX_LOCKOUT_HISTORY as u64 {
+                    vote_account_info.last_vote > bank.slot() - MAX_LOCKOUT_HISTORY as u64
+                } else {
+                    vote_account_info.last_vote > 0
+                }
             });
         Ok(RpcVoteAccountStatus {
             current: current_vote_accounts,