Re: lin-lwp and exiting threads

[Daniel Jacobowitz <drow at mvista dot com>]

On Tue, Aug 26, 2003 at 01:51:35PM -0400, Daniel Jacobowitz wrote:
> Hi Jeff,
> 
> I'm doing some work in lin-lwp.c and I saw this bit you recently committed:
> 
> +      /* Check if the current LWP has previously exited.  For nptl threads,
> +         there is no exit signal issued for LWPs that are not the
> +         main thread so we should check whenever the thread is stopped.  */
> +      if (!lin_lwp_thread_alive (lp->ptid))
> +       {
> +         if (in_thread_list (lp->ptid))
> +           {
> +             /* Core GDB cannot deal with us deleting the current
> +                thread.  */
> +             if (!ptid_equal (lp->ptid, inferior_ptid))
> +               delete_thread (lp->ptid);
> +             printf_unfiltered ("[%s exited]\n",
> +                                target_pid_to_str (lp->ptid));
> +           }
> +         if (debug_lin_lwp)
> +           fprintf_unfiltered (gdb_stdlog,
> +                               "SWC: %s already exited.\n",
>                                 target_pid_to_str (lp->ptid));
> 
> 
> This is right after waitpid has returned a non-exiting stopped status for
> lp->ptid.  Were you just being thorough, or do you have some reason to
> believe that waitpid would ever return WIFSTOPPED (status) and yet the
> thread would be dead?

Also, there's:
  pid = waitpid (GET_LWP (lp->ptid), &status, 0);
  if (pid == -1 && errno == ECHILD)
    {
      pid = waitpid (GET_LWP (lp->ptid), &status, __WCLONE);
      if (pid == -1 && errno == ECHILD)
        {
          /* The thread has previously exited.  We need to delete it now
             because in the case of NPTL threads, there won't be an
             exit event unless it is the main thread.  */
          if (debug_lin_lwp)
            fprintf_unfiltered (gdb_stdlog,
                                "SWC: %s exited.\n",
                                target_pid_to_str (lp->ptid));
          delete_lwp (lp->ptid);
          return 0;
        }
    }
  
Is there some reason you don't also call delete_thread?

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer