tetragon: Speed up tetragon pre validation

There's no need to create new btf object for each kprobe,
we can create it just once. It speeds up loading policies
with many functions.

Signed-off-by: Jiri Olsa <[email protected]>

pkg/sensors/tracing/generickprobe.go

@@ -308,6 +308,11 @@ func preValidateList(name string, lists []v1alpha1.ListSpec) error {
 // Pre validate the kprobe semantics and BTF information in order to separate
 // the kprobe errors from BPF related ones.
 func preValidateKprobes(name string, kprobes []v1alpha1.KProbeSpec, lists []v1alpha1.ListSpec) error {
+	btfobj, err := btf.NewBTF()
+	if err != nil {
+		return err
+	}
+
 	for i := range kprobes {
 		f := &kprobes[i]
 
@@ -342,11 +347,6 @@ func preValidateKprobes(name string, kprobes []v1alpha1.KProbeSpec, lists []v1al
 		}
 
 		// Now go over BTF validation
-		btfobj, err := btf.NewBTF()
-		if err != nil {
-			return err
-		}
-
 		if err := btf.ValidateKprobeSpec(btfobj, f); err != nil {
 			if warn, ok := err.(*btf.ValidationWarn); ok {
 				logger.GetLogger().WithFields(logrus.Fields{