pkg/sensors: fix potential issue in stacktrace detection

Previous condition was buggy and should have been:
hasStackTrace = hasStackTrace || KernelStackTrace || UserStackTrace
instead of :
hasStackTrace =  KernelStackTrace || UserStackTrace

Using a function simplify this.

Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com>

pkg/sensors/tracing/generickprobe.go

@@ -765,13 +765,6 @@ func addKprobe(funcName string, f *v1alpha1.KProbeSpec, in *addKprobeIn) (id idt
 		config.Syscall = 0
 	}
 
-	hasStackTrace := false
-	for _, selector := range f.Selectors {
-		for _, matchAction := range selector.MatchActions {
-			hasStackTrace = matchAction.KernelStackTrace || matchAction.UserStackTrace
-		}
-	}
-
 	// create a new entry on the table, and pass its id to BPF-side
 	// so that we can do the matching at event-generation time
 	kprobeEntry := genericKprobe{
@@ -790,7 +783,7 @@ func addKprobe(funcName string, f *v1alpha1.KProbeSpec, in *addKprobeIn) (id idt
 		customHandler:     in.customHandler,
 		message:           msgField,
 		tags:              tagsField,
-		hasStackTrace:     hasStackTrace,
+		hasStackTrace:     selectorsHaveStackTrace(f.Selectors),
 	}
 
 	// Parse Filters into kernel filter logic
@@ -1274,3 +1267,14 @@ func retprobeMerge(prev pendingEvent, curr pendingEvent) *tracing.MsgGenericKpro
 func (k *observerKprobeSensor) LoadProbe(args sensors.LoadProbeArgs) error {
 	return loadGenericKprobeSensor(args.BPFDir, args.Load, args.Verbose)
 }
+
+func selectorsHaveStackTrace(selectors []v1alpha1.KProbeSelector) bool {
+	for _, selector := range selectors {
+		for _, matchAction := range selector.MatchActions {
+			if matchAction.KernelStackTrace || matchAction.UserStackTrace {
+				return true
+			}
+		}
+	}
+	return false
+}