controller/volume/expand: Improve goroutine mgmt

Make sure all threads are terminated when Run returns.

pkg/controller/volume/expand/expand_controller.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"sync"
 	"time"
 
 	"k8s.io/klog/v2"
@@ -322,19 +323,26 @@ func (expc *expandController) expand(logger klog.Logger, pvc *v1.PersistentVolum
 // TODO make concurrency configurable (workers argument). previously, nestedpendingoperations spawned unlimited goroutines
 func (expc *expandController) Run(ctx context.Context) {
 	defer runtime.HandleCrash()
-	defer expc.queue.ShutDown()
+
 	logger := klog.FromContext(ctx)
 	logger.Info("Starting expand controller")
-	defer logger.Info("Shutting down expand controller")
+
+	var wg sync.WaitGroup
+	defer func() {
+		logger.Info("Shutting down expand controller")
+		expc.queue.ShutDown()
+		wg.Wait()
+	}()
 
 	if !cache.WaitForNamedCacheSyncWithContext(ctx, expc.pvcsSynced) {
 		return
 	}
 
 	for i := 0; i < defaultWorkerCount; i++ {
-		go wait.UntilWithContext(ctx, expc.runWorker, time.Second)
+		wg.Go(func() {
+			wait.UntilWithContext(ctx, expc.runWorker, time.Second)
+		})
 	}
-
 	<-ctx.Done()
 }