vm: check preemption string only for gce instances

Fixes #5028

4 files changed, 14 insertions, 4 deletions

diff --git a/vm/gce/gce.go b/vm/gce/gce.go
index e65ee836b..19fd1eecd 100644
--- a/vm/gce/gce.go
+++ b/vm/gce/gce.go
@@ -36,8 +36,9 @@ import (
 
 func init() {
 	vmimpl.Register("gce", vmimpl.Type{
-		Ctor:       ctor,
-		Overcommit: true,
+		Ctor:        ctor,
+		Overcommit:  true,
+		Preemptible: true,
 	})
 }
 
diff --git a/vm/vm.go b/vm/vm.go
index cc7c656cd..ca22f2be1 100644
--- a/vm/vm.go
+++ b/vm/vm.go
@@ -43,6 +43,7 @@ import (
 
 type Pool struct {
 	impl               vmimpl.Pool
+	typ                vmimpl.Type
 	workdir            string
 	template           string
 	timeouts           targets.Timeouts
@@ -128,6 +129,7 @@ func Create(cfg *mgrconfig.Config, debug bool) (*Pool, error) {
 	}
 	return &Pool{
 		impl:       impl,
+		typ:        typ,
 		workdir:    env.Workdir,
 		template:   cfg.WorkdirTemplate,
 		timeouts:   cfg.Timeouts,
@@ -420,7 +422,9 @@ func (mon *monitor) extractError(defaultError string) *report.Report {
 	if defaultError != noOutputCrash || diagWait {
 		mon.waitForOutput()
 	}
-	if bytes.Contains(mon.output, []byte(executorPreemptedStr)) {
+	// Check the executorPreemptedStr only for preemptible instances since executor can print
+	// the string spuriously in some cases (gets SIGTERM from test program somehow).
+	if mon.inst.pool.typ.Preemptible && bytes.Contains(mon.output, []byte(executorPreemptedStr)) {
 		return nil
 	}
 	if defaultError == "" && mon.reporter.ContainsCrash(mon.output[mon.matchPos:]) {
diff --git a/vm/vm_test.go b/vm/vm_test.go
index eb642830f..bede53fb7 100644
--- a/vm/vm_test.go
+++ b/vm/vm_test.go
@@ -82,7 +82,8 @@ func init() {
 		return &testPool{}, nil
 	}
 	vmimpl.Register("test", vmimpl.Type{
-		Ctor: ctor,
+		Ctor:        ctor,
+		Preemptible: true,
 	})
 }
 
diff --git a/vm/vmimpl/vmimpl.go b/vm/vmimpl/vmimpl.go
index ac38a6634..564c3e66e 100644
--- a/vm/vmimpl/vmimpl.go
+++ b/vm/vmimpl/vmimpl.go
@@ -133,6 +133,10 @@ type Type struct {
 	// It's possible to create out-of-thin-air instances of this type.
 	// Out-of-thin-air instances are used by syz-ci for image testing, patch testing, bisection, etc.
 	Overcommit bool
+	// Instances of this type can be preempted and lost connection as the result.
+	// For preempted instances executor prints "SYZ-EXECUTOR: PREEMPTED" and then
+	// the host understands that the lost connection was expected and is not a bug.
+	Preemptible bool
 }
 
 type ctorFunc func(env *Env) (Pool, error)