kernel: use the kernel context to run task destroy actions

A task context can be used only if actions are executed in a task goroutine.
In addition, these actions are executed asynchronously, so the task can be
destroyed.

Reported-by: syzbot+a9f3e03ea801374b8089@syzkaller.appspotmail.com
PiperOrigin-RevId: 706078457

pkg/sentry/kernel/task_exit.go

@@ -798,13 +798,14 @@ func (t *Task) execOnDestroyActions() {
 	if len(actions) == 0 {
 		return
 	}
+	ctx := t.k.SupervisorContext()
 	// Block S/R until all actions is executed.
 	t.k.tasks.aioGoroutines.Add(1)
 	// Run in another goroutine to avoid extra lock dependencies.
 	go func() {
 		defer t.k.tasks.aioGoroutines.Done()
 		for act := range actions {
-			act.TaskDestroyAction(t)
+			act.TaskDestroyAction(ctx)
 		}
 	}()
 }