Description:
------------
While reviewing source code for both 5.4.2 and 5.3.12 I noticed what looks like a bug in the implementation of ts_resource_ex in TSRM.c

I have not experienced a problem, but from the code it looks like there is a condition in which a mutex will be locked and never unlocked.

In TSRM.c within the implementation of ts_resource_ex, starting about line 345 I see the following:

tsrm_mutex_lock(tsmm_mutex);
...
else {
  allocate_new_resource(&thread_resources->next, thread_id);
  return ts_resource_ex(id, &thread_id);
  /*
   * thread_resources = thread_resources->next;
   * break;
   */
...			}
tsrm_mutex_unlock(tsmm_mutex);

I think the "break" in the old code that has been commented out is correct, and the "return" in the new code is uncorrect.  I think that in the event this branch of execution be taken, the tsmm_mutex will be locked but will never be unlocked.

Alternatively, if the thinking was that the recursive call to ts_resource_ex would unlock the mutex, I think there is still a problem because in this case the mutex would be locked twice, but unlocked only once.

Finally, if somehow the code is correct as it stands, it is sufficiently confusing that a comment should be added.