Enable reference count leak checking for lisafs.

Also add DoRepeatedLeakCheck() to refsvfs2 package.

Updates #5466

PiperOrigin-RevId: 425004987

pkg/lisafs/connection_test.go

@@ -104,6 +104,7 @@ func runServerClient(t testing.TB, clientFn func(c *lisafs.Client)) {
 
 	c.Close() // This should trigger client and server shutdown.
 	ts.Wait()
+	ts.Server.Destroy()
 }
 
 // TestStartUp tests that the server and client can be started up correctly.

pkg/lisafs/server.go

@@ -103,6 +103,11 @@ func (s *Server) Wait() {
 	s.connWg.Wait()
 }
 
+// Destroy releases resources being used by this server.
+func (s *Server) Destroy() {
+	s.root.DecRef(nil)
+}
+
 // ServerImpl contains the implementation details for a Server.
 // Implementations of ServerImpl should contain their associated Server by
 // value as their first field.

pkg/lisafs/testsuite/BUILD

@@ -13,6 +13,8 @@ go_library(
         "//pkg/abi/linux",
         "//pkg/context",
         "//pkg/lisafs",
+        "//pkg/refs",
+        "//pkg/refsvfs2",
         "//pkg/unet",
         "@com_github_syndtr_gocapability//capability:go_default_library",
         "@org_golang_x_sys//unix:go_default_library",

pkg/lisafs/testsuite/testsuite.go

@@ -30,6 +30,8 @@ import (
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/context"
 	"gvisor.dev/gvisor/pkg/lisafs"
+	"gvisor.dev/gvisor/pkg/refs"
+	"gvisor.dev/gvisor/pkg/refsvfs2"
 	"gvisor.dev/gvisor/pkg/unet"
 )
 
@@ -49,10 +51,9 @@ type Tester interface {
 
 // RunAllLocalFSTests runs all local FS tests as subtests.
 func RunAllLocalFSTests(t *testing.T, tester Tester) {
+	refs.SetLeakMode(refs.LeaksPanic)
 	for name, testFn := range localFSTests {
-		t.Run(name, func(t *testing.T) {
-			runServerClient(t, tester, testFn)
-		})
+		runServerClient(t, tester, name, testFn)
 	}
 }
 
@@ -74,7 +75,7 @@ var localFSTests map[string]testFunc = map[string]testFunc{
 	"Getdents":        testGetdents,
 }
 
-func runServerClient(t *testing.T, tester Tester, testFn testFunc) {
+func runServerClient(t *testing.T, tester Tester, testName string, testFn testFunc) {
 	mountPath, err := ioutil.TempDir(os.Getenv("TEST_TMPDIR"), "")
 	if err != nil {
 		t.Fatalf("creation of temporary mountpoint failed: %v", err)
@@ -109,9 +110,16 @@ func runServerClient(t *testing.T, tester Tester, testFn testFunc) {
 	rootFile := c.NewFD(root.ControlFD)
 
 	ctx := context.Background()
-	testFn(ctx, t, tester, rootFile)
+	t.Run(testName, func(t *testing.T) {
+		testFn(ctx, t, tester, rootFile)
+	})
 	closeFD(ctx, t, rootFile)
 
+	// Release server resources and check for leaks. Note that leak check must
+	// happen before c.Close() because server cleans up resources on shutdown.
+	server.Destroy()
+	refsvfs2.DoRepeatedLeakCheck()
+
 	c.Close() // This should trigger client and server shutdown.
 	server.Wait()
 }

pkg/refsvfs2/refs_map.go

@@ -124,24 +124,35 @@ func logEvent(obj CheckedObject, msg string) {
 var checkOnce sync.Once
 
 // DoLeakCheck iterates through the live object map and logs a message for each
-// object. It is called once no reference-counted objects should be reachable
-// anymore, at which point anything left in the map is considered a leak.
+// object. It should be called when no reference-counted objects are reachable
+// anymore, at which point anything left in the map is considered a leak. On
+// multiple calls, only the first call will perform the leak check.
 func DoLeakCheck() {
 	if leakCheckEnabled() {
-		checkOnce.Do(func() {
-			liveObjectsMu.Lock()
-			defer liveObjectsMu.Unlock()
-			leaked := len(liveObjects)
-			if leaked > 0 {
-				msg := fmt.Sprintf("Leak checking detected %d leaked objects:\n", leaked)
-				for obj := range liveObjects {
-					msg += obj.LeakMessage() + "\n"
-				}
-				if leakCheckPanicEnabled() {
-					panic(msg)
-				}
-				log.Warningf(msg)
-			}
-		})
+		checkOnce.Do(doLeakCheck)
+	}
+}
+
+// DoRepeatedLeakCheck is the same as DoLeakCheck except that it can be called
+// multiple times by the caller to incrementally perform leak checking.
+func DoRepeatedLeakCheck() {
+	if leakCheckEnabled() {
+		doLeakCheck()
+	}
+}
+
+func doLeakCheck() {
+	liveObjectsMu.Lock()
+	defer liveObjectsMu.Unlock()
+	leaked := len(liveObjects)
+	if leaked > 0 {
+		msg := fmt.Sprintf("Leak checking detected %d leaked objects:\n", leaked)
+		for obj := range liveObjects {
+			msg += obj.LeakMessage() + "\n"
+		}
+		if leakCheckPanicEnabled() {
+			panic(msg)
+		}
+		log.Warningf(msg)
 	}
 }

runsc/cmd/gofer.go

@@ -245,6 +245,7 @@ func (g *Gofer) serveLisafs(spec *specs.Spec, conf *config.Config, root string)
 		server.StartConnection(conn)
 	}
 	server.Wait()
+	server.Destroy()
 	log.Infof("All lisafs servers exited.")
 	return subcommands.ExitSuccess
 }