Fix the Stringer for leak mode

pkg/refs/refcounter.go

@@ -235,11 +235,11 @@ const (
 func (l LeakMode) String() string {
 	switch l {
 	case NoLeakChecking:
-		return "NoLeakChecking"
+		return "disabled"
 	case LeaksLogWarning:
-		return "LeaksLogWarning"
+		return "warning"
 	case LeaksLogTraces:
-		return "LeaksLogTraces"
+		return "traces"
 	default:
 		panic(fmt.Sprintf("Invalid leakmode: %d", l))
 	}

runsc/boot/config.go

@@ -120,6 +120,8 @@ func MakeRefsLeakMode(s string) (refs.LeakMode, error) {
 		return refs.NoLeakChecking, nil
 	case "warning":
 		return refs.LeaksLogWarning, nil
+	case "traces":
+		return refs.LeaksLogTraces, nil
 	default:
 		return 0, fmt.Errorf("invalid refs leakmode %q", s)
 	}

runsc/main.go

@@ -73,7 +73,7 @@ var (
 	netRaw             = flag.Bool("net-raw", false, "enable raw sockets. When false, raw sockets are disabled by removing CAP_NET_RAW from containers (`runsc exec` will still be able to utilize raw sockets). Raw sockets allow malicious containers to craft packets and potentially attack the network.")
 	numNetworkChannels = flag.Int("num-network-channels", 1, "number of underlying channels(FDs) to use for network link endpoints.")
 	rootless           = flag.Bool("rootless", false, "it allows the sandbox to be started with a user that is not root. Sandbox and Gofer processes may run with same privileges as current user.")
-	referenceLeakMode  = flag.String("ref-leak-mode", "disabled", "sets reference leak check mode: disabled (default), warning.")
+	referenceLeakMode  = flag.String("ref-leak-mode", "disabled", "sets reference leak check mode: disabled (default), warning, traces.")
 
 	// Test flags, not to be used outside tests, ever.
 	testOnlyAllowRunAsCurrentUserWithoutChroot = flag.Bool("TESTONLY-unsafe-nonroot", false, "TEST ONLY; do not ever use! This skips many security measures that isolate the host from the sandbox.")