Re: mark_object crash in 22.1 and latest CVS (as of tonight)

[Kalman Reti]

I looked at the code, and there are comments saying both that
the undo_list should be before the name slot and that it should
come after.  In the CVS code, it definitely comes after which looks
to me like it will get marked twice, once in the normal loop which
starts at name and marks all the following objects and then again
at the special code for marking the undo list.  This is contrary to
what the comments say should be happening, but I don't know which
of the comments or the code is right.

On Nov 12, 2007 5:03 PM, Stefan Monnier <address@hidden> wrote:
> >> The first questions are, what object contains the bad pointer?
> >> What data type is it?  What data structure is it part of?
>
> > The gdb pr output near the end of the attachment in my first message
> > shows it is part of a list, which, in turn, is part of a buffer.  I assumed
> > someone would recognize WHAT part of a buffer from the contents of the,
> > list, a mixture of conses with marker-in-no-buffer in the car of some and
> > Lisp_Misc_Free  in the car of others, the cdr's being negative numbers
> > of pretty small absolute magnitude.  If it isn't recognizable from its 
> > contents,
> > I'll have to wait till I'm next at work to find out exactly which slot
> > in the buffer
> > this list comes from using gdb.
>
> Sounds like the contents of the buffer-undo-list.  Especially since this
> variable is GC'd specially and getting it right is tricky.
>
>
>         Stefan
>