[11.0-stable] pillar/devicenetwork: fix goroutine leak

pkg/pillar/devicenetwork/dns.go

@@ -104,7 +104,11 @@ func ResolveWithPortsLambda(domain string,
 
 	quit := make(chan struct{})
 	work := make(chan struct{}, DNSMaxParallelRequests)
-	resolvedIPsChan := make(chan []DNSResponse)
+	defer close(work)
+
+	resolvedIPsChan := make(chan []DNSResponse, 1)
+	defer close(resolvedIPsChan)
+
 	countDNSRequests := 0
 	var errs []error
 	var errsMutex sync.Mutex
@@ -131,10 +135,13 @@ func ResolveWithPortsLambda(domain string,
 				copy(srcIPCopy, srcIP)
 				countDNSRequests++
 				go func(dnsIP, srcIP net.IP) {
-					select {
-					case work <- struct{}{}:
-						// if writable, means less than dnsMaxParallelRequests goroutines are currently running
-					}
+					defer func() {
+						wg.Done()
+						<-work
+					}()
+					// if writable, means less than dnsMaxParallelRequests goroutines are currently running
+					work <- struct{}{}
+
 					select {
 					case <-quit:
 						// will return in case the quit chan has been closed,
@@ -149,22 +156,28 @@ func ResolveWithPortsLambda(domain string,
 						defer errsMutex.Unlock()
 						errs = append(errs, err)
 					}
-					if response != nil {
-						resolvedIPsChan <- response
+					if response != nil && len(response) > 0 {
+						select {
+						case resolvedIPsChan <- response:
+						default:
+						}
 					}
-					<-work
-					wg.Done()
 				}(dnsIPCopy, srcIPCopy)
 			}
 		}
 	}
 
 	wgChan := make(chan struct{})
+
 	go func() {
 		wg.Wait()
 		close(wgChan)
 	}()
 
+	defer func() {
+		close(quit)
+		<-wgChan
+	}()
 	select {
 	case <-wgChan:
 		var responses []DNSResponse
@@ -183,7 +196,7 @@ func ResolveWithPortsLambda(domain string,
 		}
 		return responses, errs
 	case ip := <-resolvedIPsChan:
-		close(quit)
 		return ip, nil
 	}
+
 }

pkg/pillar/devicenetwork/dns_test.go

@@ -13,6 +13,7 @@ import (
 	"github.com/lf-edge/eve/pkg/pillar/devicenetwork"
 	"github.com/lf-edge/eve/pkg/pillar/netmonitor"
 	"github.com/lf-edge/eve/pkg/pillar/types"
+	"go.uber.org/goleak"
 )
 
 func createNetmonitorMockInterface() []netmonitor.MockInterface {
@@ -160,7 +161,7 @@ func TestDnsResolveTimeout(t *testing.T) {
 }
 
 func TestResolveWithPortsLambda(t *testing.T) {
-	t.Parallel()
+	defer goleak.VerifyNone(t, goleak.IgnoreAnyFunction("go.opencensus.io/stats/view.(*worker).start"), goleak.IgnoreCurrent())
 
 	expectedIP := net.IP{1, 2, 3, 4}
 

pkg/pillar/go.mod

@@ -128,6 +128,7 @@ require (
 	github.com/xeipuuv/gojsonschema v1.2.0 // indirect
 	github.com/yusufpapurcu/wmi v1.2.2 // indirect
 	go.opencensus.io v0.24.0 // indirect
+	go.uber.org/goleak v1.3.0 // indirect
 	golang.org/x/oauth2 v0.7.0 // indirect
 	golang.org/x/sync v0.1.0 // indirect
 	golang.org/x/text v0.13.0 // indirect

pkg/pillar/go.sum

@@ -1743,6 +1743,8 @@ go.uber.org/atomic v1.4.0/go.mod h1:gD2HeocX3+yG+ygLZcrzQJaqmWj9AIm7n08wl/qW/PE=
 go.uber.org/atomic v1.7.0/go.mod h1:fEN4uk6kAWBTFdckzkM89CLk9XfWZrxpCo0nPH17wJc=
 go.uber.org/goleak v1.1.10/go.mod h1:8a7PlsEVH3e/a/GLqe5IIrQx6GzcnRmZEufDUTk4A7A=
 go.uber.org/goleak v1.1.12/go.mod h1:cwTWslyiVhfpKIDGSZEM2HlOvcqm+tG4zioyIeLoqMQ=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/multierr v1.6.0/go.mod h1:cdWPpRnG4AhwMwsgIHip0KRBQjJy5kYEpYjJxpXp9iU=
 go.uber.org/zap v1.10.0/go.mod h1:vwi/ZaCAaUcBkycHslxD9B2zi4UTXhF60s6SWpuDF0Q=