p2p/nodestate: fix deadlock during shutdown of les server (#21927)

holiman · web-flow · commit e7db1dbc96fb · 2020-11-30T18:58:47.000+01:00
This PR fixes a deadlock reported here: #21925 The cause is that many operations may be pending, but if the close happens, only one of them gets awoken and exits, the others remain waiting for a signal that never comes.
diff --git a/p2p/nodestate/nodestate.go b/p2p/nodestate/nodestate.go
@@ -725,7 +725,7 @@ func (ns *NodeStateMachine) opFinish() {
 	}
 	ns.opPending = nil
 	ns.opFlag = false
-	ns.opWait.Signal()
+	ns.opWait.Broadcast()
 }
 
 // Operation calls the given function as an operation callback. This allows the caller

Original file line number	Diff line number	Diff line change
`@@ -725,7 +725,7 @@ func (ns *NodeStateMachine) opFinish() {`
`725`	`725`	`}`
`726`	`726`	`ns.opPending = nil`
`727`	`727`	`ns.opFlag = false`
`728`		`- ns.opWait.Signal()`
	`728`	`+ ns.opWait.Broadcast()`
`729`	`729`	`}`
`730`	`730`
`731`	`731`	`// Operation calls the given function as an operation callback. This allows the caller`