Merge pull request #58306 from liggitt/gc-nil-channel

Automatic merge from submit-queue (batch tested with PRs 58375, 58306, 58386, 57420, 58035). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Track run status explicitly rather than non-nil check on stopCh

Fixes #57044

GC and quota controllers use a non-nil stop channel as a signal Run() has been called, so ensure that condition holds even when a nil stop channel is passed in

```release-note
NONE
```

cmd/kube-controller-manager/app/controllermanager.go

@@ -171,9 +171,7 @@ func Run(s *options.CMServer) error {
 	}
 
 	if !s.LeaderElection.LeaderElect {
-		stopCh := make(chan struct{})
-		defer close(stopCh)
-		run(stopCh)
+		run(wait.NeverStop)
 		panic("unreachable")
 	}
 

pkg/controller/garbagecollector/graph_builder.go

@@ -83,13 +83,14 @@ type GraphBuilder struct {
 	// After that it is safe to start them here, before that it is not.
 	informersStarted <-chan struct{}
 
-	// stopCh drives shutdown. If it is nil, it indicates that Run() has not been
-	// called yet. If it is non-nil, then when closed it indicates everything
-	// should shut down.
-	//
+	// stopCh drives shutdown. When a receive from it unblocks, monitors will shut down.
 	// This channel is also protected by monitorLock.
 	stopCh <-chan struct{}
 
+	// running tracks whether Run() has been called.
+	// it is protected by monitorLock.
+	running bool
+
 	// metaOnlyClientPool uses a special codec, which removes fields except for
 	// apiVersion, kind, and metadata during decoding.
 	metaOnlyClientPool dynamic.ClientPool
@@ -275,7 +276,7 @@ func (gb *GraphBuilder) startMonitors() {
 	gb.monitorLock.Lock()
 	defer gb.monitorLock.Unlock()
 
-	if gb.stopCh == nil {
+	if !gb.running {
 		return
 	}
 
@@ -325,6 +326,7 @@ func (gb *GraphBuilder) Run(stopCh <-chan struct{}) {
 	// Set up the stop channel.
 	gb.monitorLock.Lock()
 	gb.stopCh = stopCh
+	gb.running = true
 	gb.monitorLock.Unlock()
 
 	// Start monitors and begin change processing until the stop channel is

pkg/controller/resourcequota/resource_quota_monitor.go

@@ -74,13 +74,14 @@ type QuotaMonitor struct {
 	// After that it is safe to start them here, before that it is not.
 	informersStarted <-chan struct{}
 
-	// stopCh drives shutdown. If it is nil, it indicates that Run() has not been
-	// called yet. If it is non-nil, then when closed it indicates everything
-	// should shut down.
-	//
+	// stopCh drives shutdown. When a receive from it unblocks, monitors will shut down.
 	// This channel is also protected by monitorLock.
 	stopCh <-chan struct{}
 
+	// running tracks whether Run() has been called.
+	// it is protected by monitorLock.
+	running bool
+
 	// monitors are the producer of the resourceChanges queue
 	resourceChanges workqueue.RateLimitingInterface
 
@@ -241,7 +242,7 @@ func (qm *QuotaMonitor) startMonitors() {
 	qm.monitorLock.Lock()
 	defer qm.monitorLock.Unlock()
 
-	if qm.stopCh == nil {
+	if !qm.running {
 		return
 	}
 
@@ -291,6 +292,7 @@ func (qm *QuotaMonitor) Run(stopCh <-chan struct{}) {
 	// Set up the stop channel.
 	qm.monitorLock.Lock()
 	qm.stopCh = stopCh
+	qm.running = true
 	qm.monitorLock.Unlock()
 
 	// Start monitors and begin change processing until the stop channel is