From ef10c6f6377955bbc709755632f21f5cb0451124 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Drwi=C4=99ga?= <tomasz@ethcore.io>
Date: Sun, 20 Mar 2016 12:18:41 +0100
Subject: [PATCH] Avoiding possible overflow when block number gets smaller.

---
 miner/src/miner.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/miner/src/miner.rs b/miner/src/miner.rs
index 699848337..e1b314d57 100644
--- a/miner/src/miner.rs
+++ b/miner/src/miner.rs
@@ -161,8 +161,8 @@ impl MinerService for Miner {
 		let should_disable_sealing = {
 			let current_no = chain.chain_info().best_block_number;
 			let last_request = self.sealing_block_last_request.lock().unwrap();
-
-			current_no - *last_request > SEALING_TIMEOUT_IN_BLOCKS
+			let is_greater = current_no > *last_request;
+			is_greater && current_no - *last_request > SEALING_TIMEOUT_IN_BLOCKS
 		};
 
 		if should_disable_sealing {