[lttng-dev] bug?

Yang Wang yangw.wang5 at unb.ca
Wed Jan 23 15:09:30 EST 2013


Hello,

I am Yang Wang, I am currently using lttng to trace my JVM.

During my using lttng in tracing JVM, I found three problems,

 1) in lttng-ust-2.1.0/include/lttng/ust-tracepoint-event.h

     why using an assertion "assert(!ret);"  (Line676)?
     not allowing double registering and init?
     if double registering or initialization (provider), why not allowed just returning silently instead
      of aborting"? How about comments assert(!ret); ==>//assert(!ret); what is the side-effects
      of doing this?

 2) The other problem is in ./userspace-rcu-0.7.5/urcu/list.h Line85

  I have to add a guard "if" statement as the assertion in my program fails otherwise

  static inline void
  __cds_list_del (struct cds_list_head *prev, struct cds_list_head *next)
  {
   if (prev != NULL && next != NULL) {
      //assert(prev != NULL && next != NULL);
      next->prev = prev;
      prev->next = next;
  }

 3) Now my instrumented prog is ready to run. Here is my commands:
     lttng create
     lttng enable-event -u -a
     lttng start
     ./prog

    The (lttng) instrumented prog is stuck there without any outputs related to lttng tracing, how can I know what happen inside.
    In other words, does lttng have any mechanism to trace itself?

   Thanks

   Yang
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