manager: fix deadlock

This fixes 2 problems:
1. syz-manager inverted condition for local instances.
2. local instances deadlocked on "no output" condition

2 files changed, 5 insertions, 2 deletions

diff --git a/syz-manager/manager.go b/syz-manager/manager.go
index dbdbdeadd..18ca57928 100644
--- a/syz-manager/manager.go
+++ b/syz-manager/manager.go
@@ -260,7 +260,7 @@ func (mgr *Manager) runInstance(vmCfg *vm.Config, first bool) bool {
 		return false
 	}
 
-	desc, text, output, crashed, timedout := vm.MonitorExecution(outc, errc, mgr.cfg.Type != "local", true)
+	desc, text, output, crashed, timedout := vm.MonitorExecution(outc, errc, mgr.cfg.Type == "local", true)
 	if timedout {
 		// This is the only "OK" outcome.
 		logf(0, "%v: running long enough, restarting", vmCfg.Name)
diff --git a/vm/vm.go b/vm/vm.go
index 25d5010da..ac60c8de0 100644
--- a/vm/vm.go
+++ b/vm/vm.go
@@ -107,10 +107,12 @@ func MonitorExecution(outc <-chan []byte, errc <-chan error, local, needOutput b
 	)
 	lastExecuteTime := time.Now()
 	ticker := time.NewTimer(3 * time.Minute)
+	tickerFired := false
 	for {
-		if !ticker.Stop() {
+		if !tickerFired && !ticker.Stop() {
 			<-ticker.C
 		}
+		tickerFired = false
 		ticker.Reset(3 * time.Minute)
 		select {
 		case err := <-errc:
@@ -160,6 +162,7 @@ func MonitorExecution(outc <-chan []byte, errc <-chan error, local, needOutput b
 				return "test machine is not executing programs", nil, output, true, false
 			}
 		case <-ticker.C:
+			tickerFired = true
 			if !local {
 				return "no output from test machine", nil, output, true, false
 			}