From eb0fd3625a3534e80aeb117180fdf767af39072e Mon Sep 17 00:00:00 2001
From: "mergify[bot]" <37929162+mergify[bot]@users.noreply.github.com>
Date: Mon, 28 Dec 2020 02:34:58 +0000
Subject: [PATCH] Fix subtraction overflow in metrics (#14290) (#14296)

(cherry picked from commit c693ffaa08361ad1dab47e7110c5488e2dc9eb3c)

Co-authored-by: sakridge <sakridge@gmail.com>
---
 core/src/broadcast_stage.rs  | 2 +-
 core/src/retransmit_stage.rs | 7 +++++--
 runtime/src/accounts_db.rs   | 2 +-
 3 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/core/src/broadcast_stage.rs b/core/src/broadcast_stage.rs
index 484dc0e39f..83a238a2df 100644
--- a/core/src/broadcast_stage.rs
+++ b/core/src/broadcast_stage.rs
@@ -347,7 +347,7 @@ fn update_peer_stats(
 ) {
     let now = timestamp();
     let last = last_datapoint_submit.load(Ordering::Relaxed);
-    if now - last > 1000
+    if now.saturating_sub(last) > 1000
         && last_datapoint_submit.compare_and_swap(last, now, Ordering::Relaxed) == last
     {
         datapoint_info!(
diff --git a/core/src/retransmit_stage.rs b/core/src/retransmit_stage.rs
index 7b482d7e54..a218bad95d 100644
--- a/core/src/retransmit_stage.rs
+++ b/core/src/retransmit_stage.rs
@@ -117,7 +117,9 @@ fn update_retransmit_stats(
 
     let now = timestamp();
     let last = stats.last_ts.load(Ordering::Relaxed);
-    if now - last > 2000 && stats.last_ts.compare_and_swap(last, now, Ordering::Relaxed) == last {
+    if now.saturating_sub(last) > 2000
+        && stats.last_ts.compare_and_swap(last, now, Ordering::Relaxed) == last
+    {
         datapoint_info!("retransmit-num_nodes", ("count", peers_len, i64));
         datapoint_info!(
             "retransmit-stage",
@@ -288,7 +290,8 @@ fn retransmit(
 
     let now = timestamp();
     let last = last_peer_update.load(Ordering::Relaxed);
-    if now - last > 1000 && last_peer_update.compare_and_swap(last, now, Ordering::Relaxed) == last
+    if now.saturating_sub(last) > 1000
+        && last_peer_update.compare_and_swap(last, now, Ordering::Relaxed) == last
     {
         drop(r_epoch_stakes_cache);
         let mut w_epoch_stakes_cache = epoch_stakes_cache.write().unwrap();
diff --git a/runtime/src/accounts_db.rs b/runtime/src/accounts_db.rs
index 0096a0282e..793fe3d298 100644
--- a/runtime/src/accounts_db.rs
+++ b/runtime/src/accounts_db.rs
@@ -2723,7 +2723,7 @@ impl AccountsDB {
     fn report_store_timings(&self) {
         let last = self.stats.last_store_report.load(Ordering::Relaxed);
         let now = solana_sdk::timing::timestamp();
-        if now - last > 1000
+        if now.saturating_sub(last) > 1000
             && self
                 .stats
                 .last_store_report