Re: delete-process bug

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Thanks for working on this.  I agree that `live_deleted_processes'
> is a good name.  ("Zombie process" has a different meaning.)

> However, maybe there is still a race condition.  Suppose the signal
> comes in the middle of the line

>     +      live_deleted_processes = Fcons (make_number (p->pid),
>     +				      /* GC previous elements.  */
>     +				      Fdelq (Qnil, live_deleted_processes));

> Suppose it comes between there and the call to remove_process?

I think it's OK: if the signal handler comes before the assignment to
live_deleted_processes, then it'll all behave as if the signal came even
before the call to delete-process.  If it comes afterwards, the signal will
be ignored (as if it came after the call to delete-process).

> Does the right thing happen in all these cases?

I believe so.

> Also, please remember that in Emacs braces go on lines by themselves:

> +      tail = Fmemq (make_number (pid), live_deleted_processes);
> +      if (!NILP (tail)) {
> +	Fsetcar (tail, Qnil);
> +	return;
> +      }

I do remember, but indeed I missed this one.  Thanks for spotting it.


        Stefan