Merge branch 'release/0.9.23'v0.9.23

3 files changed, 29 insertions, 13 deletions

diff --git a/miner/agent.go b/miner/agent.go
index da2a2008d..3ed3ba839 100644
--- a/miner/agent.go
+++ b/miner/agent.go
@@ -40,7 +40,6 @@ func (self *CpuAgent) Stop() {
 	defer self.mu.Unlock()
 
 	close(self.quit)
-	close(self.quitCurrentOp)
 }
 
 func (self *CpuAgent) Start() {
@@ -50,7 +49,6 @@ func (self *CpuAgent) Start() {
 	self.quit = make(chan struct{})
 	// creating current op ch makes sure we're not closing a nil ch
 	// later on
-	self.quitCurrentOp = make(chan struct{})
 	self.workCh = make(chan *types.Block, 1)
 
 	go self.update()
@@ -62,11 +60,19 @@ out:
 		select {
 		case block := <-self.workCh:
 			self.mu.Lock()
-			close(self.quitCurrentOp)
+			if self.quitCurrentOp != nil {
+				close(self.quitCurrentOp)
+			}
+			self.quitCurrentOp = make(chan struct{})
+			go self.mine(block, self.quitCurrentOp)
 			self.mu.Unlock()
-
-			go self.mine(block)
 		case <-self.quit:
+			self.mu.Lock()
+			if self.quitCurrentOp != nil {
+				close(self.quitCurrentOp)
+				self.quitCurrentOp = nil
+			}
+			self.mu.Unlock()
 			break out
 		}
 	}
@@ -84,16 +90,11 @@ done:
 	}
 }
 
-func (self *CpuAgent) mine(block *types.Block) {
+func (self *CpuAgent) mine(block *types.Block, stop <- chan struct{}) {
 	glog.V(logger.Debug).Infof("(re)started agent[%d]. mining...\n", self.index)
 
-	// Reset the channel
-	self.mu.Lock()
-	self.quitCurrentOp = make(chan struct{})
-	self.mu.Unlock()
-
 	// Mine
-	nonce, mixDigest := self.pow.Search(block, self.quitCurrentOp)
+	nonce, mixDigest := self.pow.Search(block, stop)
 	if nonce != 0 {
 		block.SetNonce(nonce)
 		block.Header().MixDigest = common.BytesToHash(mixDigest)
diff --git a/miner/miner.go b/miner/miner.go
index 3f87e8151..4e99245f8 100644
--- a/miner/miner.go
+++ b/miner/miner.go
@@ -39,6 +39,10 @@ func New(eth core.Backend, mux *event.TypeMux, pow pow.PoW) *Miner {
 	return miner
 }
 
+// update keeps track of the downloader events. Please be aware that this is a one shot type of update loop.
+// It's entered once and as soon as `Done` or `Failed` has been broadcasted the events are unregistered and
+// the loop is exited. This to prevent a major security vuln where external parties can DOS you with blocks
+// and halt your mining operation for as long as the DOS continues.
 func (self *Miner) update() {
 	events := self.mux.Subscribe(downloader.StartEvent{}, downloader.DoneEvent{}, downloader.FailedEvent{})
 	for ev := range events.Chan() {
@@ -59,6 +63,10 @@ func (self *Miner) update() {
 				self.Start(self.coinbase, self.threads)
 			}
 		}
+		// unsubscribe. we're only interested in this event once
+		events.Unsubscribe()
+		// stop immediately and ignore all further pending events
+		break
 	}
 }
 
diff --git a/miner/worker.go b/miner/worker.go
index d5f9dd8c5..5e4ff7510 100644
--- a/miner/worker.go
+++ b/miner/worker.go
@@ -224,7 +224,13 @@ func (self *worker) wait() {
 				}
 				self.mux.Post(core.NewMinedBlockEvent{block})
 
-				glog.V(logger.Info).Infof("🔨  Mined block #%v", block.Number())
+				var stale string
+				canonBlock := self.chain.GetBlockByNumber(block.NumberU64())
+				if canonBlock != nil && canonBlock.Hash() != block.Hash() {
+					stale = "stale-"
+				}
+
+				glog.V(logger.Info).Infof("🔨  Mined %sblock #%v (%x)", stale, block.Number(), block.Hash().Bytes()[:4])
 
 				jsonlogger.LogJson(&logger.EthMinerNewBlock{
 					BlockHash:     block.Hash().Hex(),
@@ -264,6 +270,7 @@ func (self *worker) makeCurrent() {
 	}
 	block.Header().Extra = self.extra
 
+	// when 08 is processed ancestors contain 07 (quick block)
 	current := env(block, self.eth)
 	for _, ancestor := range self.chain.GetAncestors(block, 7) {
 		for _, uncle := range ancestor.Uncles() {