link: do not attempt to clean up perf event and tracefs event in order

Switching to runtime.AddCleanup means that cleanups may be batched and
may run concurrently. Since both the perf event and the tracefs event
will have a cleanup attached it's not possible to guarantee an ordering.

Drop the code which tries to clean up in order when the object is leaked
without calling Close().

Signed-off-by: Lorenz Bauer <[email protected]>

Author: lmb

link/perf_event.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"fmt"
 	"os"
-	"runtime"
 	"unsafe"
 
 	"github.com/cilium/ebpf"
@@ -61,15 +60,11 @@ type perfEvent struct {
 
 func newPerfEvent(fd *sys.FD, event *tracefs.Event) *perfEvent {
 	pe := &perfEvent{event, fd}
-	// Both event and fd have their own finalizer, but we want to
-	// guarantee that they are closed in a certain order.
-	runtime.SetFinalizer(pe, (*perfEvent).Close)
 	return pe
 }
 
 func (pe *perfEvent) Close() error {
-	runtime.SetFinalizer(pe, nil)
-
+	// We close the perf event before attempting to remove the tracefs event.
 	if err := pe.fd.Close(); err != nil {
 		return fmt.Errorf("closing perf event fd: %w", err)
 	}