bug#24751: 26.0.50; Regex stack overflow not detected properly (gets "Variable binding depth exceeds max-specpdl-size")

[Eli Zaretskii]

> From: npostavs@users.sourceforge.net
> Cc: 24751@debbugs.gnu.org
> Date: Tue, 15 Nov 2016 20:06:29 -0500
> 
> >> @@ -869,6 +869,7 @@ main (int argc, char **argv)
> >>  
> >>        /* Don't let regex.c overflow the stack.  */
> >>        re_max_failures = lim < extra ? 0 : min (lim - extra, SIZE_MAX) / 
> >> ratio;
> >> +      emacs_re_safe_alloca = re_max_failures * min_ratio;
> >>      }
> >>  #endif /* HAVE_SETRLIMIT and RLIMIT_STACK and not CYGWIN */
> >
> >   . we shouldn't set re_max_failures to zero if the amount of stack is
> >     less than 'extra', since in that case we will allocate the failure
> >     stack off the heap;
> 
> Then what should we set it to?  Maybe we shouldn't modify it at all,
> since the stack isn't actually a limiting factor?

Yes, I think this is the best solution.

Thanks.