fix(ebpf): start profiling after attaching perf reader (#2812)

Author: korniltsev

ebpf/session.go

@@ -163,15 +163,15 @@ func (s *session) Start() error {
 
 	btf.FlushKernelSpec() // save some memory
 
-	s.perfEvents, err = attachPerfEvents(s.options.SampleRate, s.bpf.DoPerfEvent)
+	eventsReader, err := perf.NewReader(s.bpf.ProfileMaps.Events, 4*os.Getpagesize())
 	if err != nil {
 		s.stopLocked()
-		return fmt.Errorf("attach perf events: %w", err)
+		return fmt.Errorf("perf new reader for events map: %w", err)
 	}
-	eventsReader, err := perf.NewReader(s.bpf.ProfileMaps.Events, 4*os.Getpagesize())
+	s.perfEvents, err = attachPerfEvents(s.options.SampleRate, s.bpf.DoPerfEvent)
 	if err != nil {
 		s.stopLocked()
-		return fmt.Errorf("perf new reader for events map: %w", err)
+		return fmt.Errorf("attach perf events: %w", err)
 	}
 
 	err = s.linkKProbes()