webconsole: fix defer order to release zombie process

pkg/webconsole/service/service.go

@@ -26,6 +26,7 @@ import (
 	"github.com/gorilla/mux"
 
 	"yunion.io/x/log"
+	"yunion.io/x/pkg/util/signalutils"
 
 	api "yunion.io/x/onecloud/pkg/apis/webconsole"
 	"yunion.io/x/onecloud/pkg/appsrv"
@@ -66,9 +67,15 @@ func StartService() {
 
 	common_options.StartOptionManager(opts, opts.ConfigSyncPeriodSeconds, api.SERVICE_TYPE, api.SERVICE_VERSION, o.OnOptionsChange)
 
+	registerSigTraps()
 	start()
 }
 
+func registerSigTraps() {
+	signalutils.SetDumpStackSignal()
+	signalutils.StartTrap()
+}
+
 func start() {
 	baseOpts := &o.Options.BaseOptions
 	// commonOpts := &o.Options.CommonOptions

pkg/webconsole/session/pty_session.go

@@ -102,6 +102,10 @@ func (p *Pty) Resize(size *pty.Winsize) {
 func (p *Pty) Stop() (err error) {
 	var errs []error
 
+	defer func() {
+		p.Cmd, p.Pty = nil, nil
+	}()
+
 	defer func() {
 		err = errors.NewAggregate(errs)
 	}()
@@ -139,8 +143,5 @@ func (p *Pty) Stop() (err error) {
 		}
 	}()
 
-	defer func() {
-		p.Cmd, p.Pty = nil, nil
-	}()
 	return
 }