syz-manager: repair VM-less mode

VM-less mode stopped working after addition of RPCServer.createInstance.
Repair it.

3 files changed, 19 insertions, 5 deletions

diff --git a/pkg/mgrconfig/load.go b/pkg/mgrconfig/load.go
index cfe26c573..db44caa89 100644
--- a/pkg/mgrconfig/load.go
+++ b/pkg/mgrconfig/load.go
@@ -36,6 +36,11 @@ type Derived struct {
 	Syscalls      []int
 	NoMutateCalls map[int]bool // Set of IDs of syscalls which should not be mutated.
 	Timeouts      targets.Timeouts
+
+	// Special debugging/development mode specified by VM type "none".
+	// In this mode syz-manager does not start any VMs, but instead a user is supposed
+	// to start syz-fuzzer process in a VM manually.
+	VMLess bool
 }
 
 func LoadData(data []byte) (*Config, error) {
@@ -191,6 +196,7 @@ func Complete(cfg *Config) error {
 		}
 	}
 	cfg.initTimeouts()
+	cfg.VMLess = cfg.Type == "none"
 	return nil
 }
 
diff --git a/syz-manager/manager.go b/syz-manager/manager.go
index 8c4b35f2b..44df6d9fd 100644
--- a/syz-manager/manager.go
+++ b/syz-manager/manager.go
@@ -174,10 +174,7 @@ func RunManager(cfg *mgrconfig.Config) {
 	}
 
 	var vmPool *vm.Pool
-	// Type "none" is a special case for debugging/development when manager
-	// does not start any VMs, but instead you start them manually
-	// and start syz-fuzzer there.
-	if cfg.Type != "none" {
+	if !cfg.VMLess {
 		var err error
 		vmPool, err = vm.Create(cfg, *flagDebug)
 		if err != nil {
diff --git a/syz-manager/rpc.go b/syz-manager/rpc.go
index 839adba1c..6fdb1c0ce 100644
--- a/syz-manager/rpc.go
+++ b/syz-manager/rpc.go
@@ -136,6 +136,15 @@ func (serv *RPCServer) handleConn(conn *flatrpc.Conn) {
 		return
 	}
 
+	if serv.cfg.VMLess {
+		// There is no VM loop, so minic what it would do.
+		serv.createInstance(name, nil)
+		defer func() {
+			serv.stopFuzzing(name)
+			serv.shutdownInstance(name, false)
+		}()
+	}
+
 	serv.mu.Lock()
 	runner := serv.runners[name]
 	if runner == nil || runner.stopped {
@@ -168,7 +177,9 @@ func (serv *RPCServer) handshake(conn *flatrpc.Conn) (string, []byte, *cover.Can
 	}
 	connectReq := connectReqRaw.UnPack()
 	log.Logf(1, "fuzzer %v connected", connectReq.Name)
-	checkRevisions(connectReq, serv.cfg.Target)
+	if !serv.cfg.VMLess {
+		checkRevisions(connectReq, serv.cfg.Target)
+	}
 	serv.statVMRestarts.Add(1)
 
 	bugFrames := serv.mgr.currentBugFrames()