diff --git a/core/src/replay_stage.rs b/core/src/replay_stage.rs
index a6857faed..bd1adf9f6 100644
--- a/core/src/replay_stage.rs
+++ b/core/src/replay_stage.rs
@@ -6752,8 +6752,11 @@ pub(crate) mod tests {
             "retry_iteration=0, elapsed < 2^0 * RETRANSMIT_BASE_DELAY_MS"
         );
 
-        progress.get_retransmit_info_mut(0).unwrap().retry_time =
-            Some(Instant::now() - Duration::from_millis(RETRANSMIT_BASE_DELAY_MS + 1));
+        progress.get_retransmit_info_mut(0).unwrap().retry_time = Some(
+            Instant::now()
+                .checked_sub(Duration::from_millis(RETRANSMIT_BASE_DELAY_MS + 1))
+                .unwrap(),
+        );
         ReplayStage::retransmit_latest_unpropagated_leader_slot(
             &poh_recorder,
             &retransmit_slots_sender,
@@ -6781,8 +6784,11 @@ pub(crate) mod tests {
             "retry_iteration=1, elapsed < 2^1 * RETRY_BASE_DELAY_MS"
         );
 
-        progress.get_retransmit_info_mut(0).unwrap().retry_time =
-            Some(Instant::now() - Duration::from_millis(RETRANSMIT_BASE_DELAY_MS + 1));
+        progress.get_retransmit_info_mut(0).unwrap().retry_time = Some(
+            Instant::now()
+                .checked_sub(Duration::from_millis(RETRANSMIT_BASE_DELAY_MS + 1))
+                .unwrap(),
+        );
         ReplayStage::retransmit_latest_unpropagated_leader_slot(
             &poh_recorder,
             &retransmit_slots_sender,
@@ -6794,8 +6800,11 @@ pub(crate) mod tests {
             "retry_iteration=1, elapsed < 2^1 * RETRANSMIT_BASE_DELAY_MS"
         );
 
-        progress.get_retransmit_info_mut(0).unwrap().retry_time =
-            Some(Instant::now() - Duration::from_millis(2 * RETRANSMIT_BASE_DELAY_MS + 1));
+        progress.get_retransmit_info_mut(0).unwrap().retry_time = Some(
+            Instant::now()
+                .checked_sub(Duration::from_millis(2 * RETRANSMIT_BASE_DELAY_MS + 1))
+                .unwrap(),
+        );
         ReplayStage::retransmit_latest_unpropagated_leader_slot(
             &poh_recorder,
             &retransmit_slots_sender,
@@ -6818,8 +6827,11 @@ pub(crate) mod tests {
             .unwrap()
             .increment_retry_iteration();
 
-        progress.get_retransmit_info_mut(0).unwrap().retry_time =
-            Some(Instant::now() - Duration::from_millis(2 * RETRANSMIT_BASE_DELAY_MS + 1));
+        progress.get_retransmit_info_mut(0).unwrap().retry_time = Some(
+            Instant::now()
+                .checked_sub(Duration::from_millis(2 * RETRANSMIT_BASE_DELAY_MS + 1))
+                .unwrap(),
+        );
         ReplayStage::retransmit_latest_unpropagated_leader_slot(
             &poh_recorder,
             &retransmit_slots_sender,
@@ -6831,8 +6843,11 @@ pub(crate) mod tests {
             "retry_iteration=3, elapsed < 2^3 * RETRANSMIT_BASE_DELAY_MS"
         );
 
-        progress.get_retransmit_info_mut(0).unwrap().retry_time =
-            Some(Instant::now() - Duration::from_millis(8 * RETRANSMIT_BASE_DELAY_MS + 1));
+        progress.get_retransmit_info_mut(0).unwrap().retry_time = Some(
+            Instant::now()
+                .checked_sub(Duration::from_millis(8 * RETRANSMIT_BASE_DELAY_MS + 1))
+                .unwrap(),
+        );
         ReplayStage::retransmit_latest_unpropagated_leader_slot(
             &poh_recorder,
             &retransmit_slots_sender,
diff --git a/dos/src/main.rs b/dos/src/main.rs
index ec472fd2d..1409e90e3 100644
--- a/dos/src/main.rs
+++ b/dos/src/main.rs
@@ -104,7 +104,9 @@ impl TransactionGenerator {
     fn new(transaction_params: TransactionParams) -> Self {
         TransactionGenerator {
             blockhash: Hash::default(),
-            last_generated: (Instant::now() - Duration::from_secs(100)), //to force generation when generate is called
+            last_generated: Instant::now()
+                .checked_sub(Duration::from_secs(100))
+                .unwrap(), //to force generation when generate is called
             transaction_params,
         }
     }
diff --git a/runtime/src/accounts_db.rs b/runtime/src/accounts_db.rs
index 3011755ce..8e5d4df69 100644
--- a/runtime/src/accounts_db.rs
+++ b/runtime/src/accounts_db.rs
@@ -15657,8 +15657,9 @@ pub mod tests {
         assert_eq!(recycle_stores.total_bytes(), store_file_size * 2);
 
         // expiration for only too old entries
-        recycle_stores.entries[0].0 =
-            Instant::now() - Duration::from_secs(EXPIRATION_TTL_SECONDS + 1);
+        recycle_stores.entries[0].0 = Instant::now()
+            .checked_sub(Duration::from_secs(EXPIRATION_TTL_SECONDS + 1))
+            .unwrap();
         let expired = recycle_stores.expire_old_entries();
         assert_eq!(
             expired