bug#17986: 24.3.92; Evaluating (setq default-directory nil) freezes Emacs

[Stephen Berman <stephen.berman@gmx.net>]

On Sun, 13 Jul 2014 17:54:35 +0300 Eli Zaretskii <eliz@gnu.org> wrote:

>> From: Stephen Berman <stephen.berman@gmx.net>
>> Date: Thu, 10 Jul 2014 14:27:30 +0200
>> 
>> 0. Start Emacs with -Q or -Q -D
>> 1. Type (setq default-directory nil) in *scratch* and evaluate it.
>> => Emacs freezes uninterruptibly and uses up to 90% CPU; I have to kill
>> it from outside.
>
> Should be fixed in revision 117376 on the emacs-24 branch.

For the record, I confirm that this fixes it; thanks.

> When Emacs becomes unresponsive, it is best to attach a debugger to a
> running Emacs process, and then use the procedure described in
> etc/DEBUG (under "If the symptom of the bug is that Emacs fails to
> respond") to find out which function infloops; then include this
> information in the bug report.

I tried doing this, but neither with `s' nor with `f' did gdb show what
I could recognize as an infloop (`f' always went straight to frame #0,
and `s' never got to a loop, though I entered it very many times).  Is
there something more specific I could do the next time?

Steve Berman